Python: fix: prevent inner_exception from being lost in AgentFrameworkException

[Bahtya]

Problem

AgentFrameworkException.__init__() unconditionally calls super().__init__(message, *args) after the conditional super().__init__(message, inner_exception, *args). When inner_exception is provided, the second call overwrites the exception args, losing the inner exception reference.

Root Cause

Missing else branch — both super().__init__() calls execute when inner_exception is truthy.

Fix

Add else: branch so super().__init__() is called exactly once with the correct arguments.

Before:

if inner_exception:
    super().__init__(message, inner_exception, *args)
super().__init__(message, *args)  # always runs, overwrites args

After:

if inner_exception:
    super().__init__(message, inner_exception, *args)
else:
    super().__init__(message, *args)

Fixes #5155