Fix Error Handling and None Value Processing in Templates Aggregation Pipeline

PR description

This PR addresses critical error handling issues and improves robustness when processing None values in the templates aggregation pipeline and output builders.

Issue

Several error handling and None value processing issues were identified:

1. Incorrect error handling method calls: The templates aggregation pipeline was calling _handle_execution_error instead of the correct error manager
2. None value crashes in output builders: Output builders were not properly handling cases where aggregation_result is None, causing crashes during metadata extraction
3. Missing error handling for input validation: Template/image ID validation errors were not properly caught and handled
4. Insufficient test coverage: Missing tests for failure scenarios and edge cases with None values

Solution

Error Handling Improvements:

• Fixed error handling in TemplatesAggregationPipeline: Replaced incorrect _handle_execution_error(None, e) call with proper self.env.error_manager(self.call_trace, e) usage
• Added comprehensive input validation error handling: Wrapped template/image ID validation logic in try-catch blocks to gracefully handle validation failures
• Improved pipeline robustness: Ensured pipeline returns proper error responses instead of crashing when validation fails

None Value Processing:

• Enhanced output builders: Updated MULTIFRAME_IRIS_PIPE_ORB_OUTPUT_SPEC and MULTIFRAME_IRIS_PIPE_SIMPLE_ORB_OUTPUT_SPEC to safely handle None aggregation_result values using walrus operator pattern
• Safe metadata extraction: Implemented null-safe extractors that return None when aggregation_result is missing rather than raising exceptions

Limitations

• Error messages are logged but may not provide detailed context about which specific template or image ID caused the validation failure
• The automatic fallback behavior when errors occur may mask underlying issues in some debugging scenarios
• Some edge cases with complex error chaining scenarios may still require additional handling

Type

• Feature
• Refactoring
• Bugfix
• DevOps
• Testing

Checklist

• I've made sure that my code works as expected by writing unit tests.
• I've checked if my code doesn't generate warnings or errors.
• I've performed a self-review of my code.
• I've made sure that my code follows the style guidelines of the project.
• I've commented hard-to-understand parts of my code.
• I've made appropriate changes in the documentation.