Add record accessor support in parser filter

[agup006]

Summary

• allow Parser filter to parse nested keys using record accessor patterns
• clean up parser context on exit

Testing

• cmake .. -DFLB_TESTS_INTERNAL=Off -DFLB_TESTS_RUNTIME=Off
• make -j$(nproc)
• ctest --output-on-failure

[Copilot]

Pull Request Overview

This PR adds support for record accessor patterns in the parser filter by integrating record accessor functionality and ensuring proper cleanup of parser context.

• Added header includes and a new ra_key field for record accessor support in the filter_parser_ctx structure.
• Updated the configuration and filtering functions to create and use ra_key when keys start with '$'.
• Ensured that the ra_key is destroyed during filter exit for proper resource cleanup.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
plugins/filter_parser/filter_parser.h	Added necessary includes and a new field for record accessor support.
plugins/filter_parser/filter_parser.c	Configured record accessor creation, usage in filtering, and cleanup on exit.

Comments suppressed due to low confidence (1)

plugins/filter_parser/filter_parser.c:262

• [nitpick] Consider renaming 'rval' to 'ra_value' for better clarity, as it represents a record accessor value.

rval = flb_ra_get_value_object(ctx->ra_key, *obj);

[Copilot]

[nitpick] Consider adding a brief comment here to explain that keys starting with '$' are processed as record accessor patterns.