Fix ExecutorRetryConfig null pointer exception

Fixed casting issue in ExecutorConfig where opts.retry Map was incorrectly
cast to ExecutorRetryConfig, resulting in null value and subsequent NPE
when calling getReason(). Now properly instantiates ExecutorRetryConfig
from Map or creates default instance.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: pditommaso

modules/nextflow/src/main/groovy/nextflow/executor/ExecutorConfig.groovy

@@ -176,7 +176,7 @@ class ExecutorConfig implements ConfigScope {
         queueGlobalStatus = opts.queueGlobalStatus as boolean
         queueSize = opts.queueSize as Integer
         queueStatInterval = opts.queueStatInterval as Duration ?: Duration.of('1min')
-        retry = opts.retry as ExecutorRetryConfig
+        retry = opts.retry ? new ExecutorRetryConfig(opts.retry as Map) : new ExecutorRetryConfig(Map.of())
         submitRateLimit = opts.submitRateLimit
 
         // preserve executor-specific opts