fix(llmobs): remove version setting in langchain auto prompt template (#14937)

## Description
Remove setting version from auto instrumented prompt templates.
We adjusted the way we interpret explicitly set versions. Auto
instrumentation should not set one.

## Testing

<!-- Describe your testing strategy or note what tests are included -->

## Risks

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-->

## Additional Notes

<!-- Any other information that would be helpful for reviewers -->

(cherry picked from commit 8b7fe13)

Author: jsimpher

ddtrace/llmobs/_integrations/langchain.py

@@ -915,7 +915,6 @@ def handle_prompt_template_invoke(self, instance, result, args: List[Any], kwarg
             "template": template,
             "chat_template": chat_template,
             "id": prompt_id if prompt_id is not None else "unknown",
-            "version": "0.0.0",
             "rag_context_variables": [],
             "rag_query_variables": [],
             "tags": tags,

releasenotes/notes/fix-langchain-auto-prompt-version-983dd20c5f070f9f.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    langchain: This fix resolves an issue where auto instrumented prompt templates incorrectly included a
+    ``version`` field. The version field is now omitted unless explicitly set by the user.

tests/contrib/langchain/test_langchain_llmobs.py

@@ -414,7 +414,6 @@ def test_llmobs_chain(langchain_core, langchain_openai, openai_url, llmobs_event
                 {"content": "{input}", "role": "user"},
             ],
             "variables": {"input": "Can you explain what an LLM chain is?"},
-            "version": "0.0.0",
             "_dd_context_variable_keys": ["context"],
             "_dd_query_variable_keys": ["question"],
         },
@@ -456,7 +455,6 @@ def test_llmobs_chain_nested(langchain_core, langchain_openai, openai_url, llmob
             "id": "langchain.unknown_prompt_template",
             "chat_template": [{"content": "what is the city {person} is from?", "role": "user"}],
             "variables": {"person": "Spongebob Squarepants", "language": "Spanish"},
-            "version": "0.0.0",
             "_dd_context_variable_keys": ["context"],
             "_dd_query_variable_keys": ["question"],
         },
@@ -469,7 +467,6 @@ def test_llmobs_chain_nested(langchain_core, langchain_openai, openai_url, llmob
             "id": "test_langchain_llmobs.prompt2",
             "chat_template": [{"content": "what country is the city {city} in? respond in {language}", "role": "user"}],
             "variables": {"city": mock.ANY, "language": "Spanish"},
-            "version": "0.0.0",
             "_dd_context_variable_keys": ["context"],
             "_dd_query_variable_keys": ["question"],
         },
@@ -505,7 +502,6 @@ def test_llmobs_chain_batch(langchain_core, langchain_openai, llmobs_events, tra
                 "id": "langchain.unknown_prompt_template",
                 "chat_template": [{"content": "Tell me a short joke about {topic}", "role": "user"}],
                 "variables": {"topic": "chickens"},
-                "version": "0.0.0",
                 "_dd_context_variable_keys": ["context"],
                 "_dd_query_variable_keys": ["question"],
             },
@@ -519,7 +515,6 @@ def test_llmobs_chain_batch(langchain_core, langchain_openai, llmobs_events, tra
                 "id": "langchain.unknown_prompt_template",
                 "chat_template": [{"content": "Tell me a short joke about {topic}", "role": "user"}],
                 "variables": {"topic": "pigs"},
-                "version": "0.0.0",
                 "_dd_context_variable_keys": ["context"],
                 "_dd_query_variable_keys": ["question"],
             },
@@ -534,7 +529,6 @@ def test_llmobs_chain_batch(langchain_core, langchain_openai, llmobs_events, tra
                 "id": "langchain.unknown_prompt_template",
                 "chat_template": [{"content": "Tell me a short joke about {topic}", "role": "user"}],
                 "variables": {"topic": "chickens"},
-                "version": "0.0.0",
                 "_dd_context_variable_keys": ["context"],
                 "_dd_query_variable_keys": ["question"],
             },
@@ -548,7 +542,6 @@ def test_llmobs_chain_batch(langchain_core, langchain_openai, llmobs_events, tra
                 "id": "langchain.unknown_prompt_template",
                 "chat_template": [{"content": "Tell me a short joke about {topic}", "role": "user"}],
                 "variables": {"topic": "pigs"},
-                "version": "0.0.0",
                 "_dd_context_variable_keys": ["context"],
                 "_dd_query_variable_keys": ["question"],
             },