Remove direct access to v2.Context.StatusReporter in Filestream

[belimawr]

Proposed commit message

v2.Context.StatusReporter can be nil when Filebeat runs standalone. The direct access to this field is replaced in Filestream by the UpdateStatus method. A deprecation notice is added is added to the StatusReporter field.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works. Where relevant, I have used the stresstest.sh script to run them under stress conditions and race detector to verify their stability.
• I have added an entry in ./changelog/fragments using the changelog tool.

## Disruptive User Impact
## Author's Checklist

How to test this PR locally

1. Create a log file

docker run -it --rm mingrammer/flog -n 50 > /tmp/flog.ndjson

2. Run Filebeat with the following configuration

filebeat.yml

filebeat.inputs:
  - type: filestream
    id: filestream-input-id
    paths:
      - /tmp/flog.log
    processors:
      - add_fields:
          INVALID_CONFIG_KEY: true
          fields:
            labels:
              foo: bar

logging:
  to_stderr: true

output.discard:
  enabled: true

It should not panic

## Related issues
## Use cases
## Screenshots
## Logs

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)

[github-actions]

🤖 GitHub comments

Just comment with:

• run docs-build : Re-trigger the docs validation. (use unformatted text in the comment!)

[github-actions]

@Mergifyio backport 8.19 9.1 9.2

[mergify]

backport 8.19 9.1 9.2

✅ Backports have been created

• #48076 [8.19](backport #48075) Remove direct access to v2.Context.StatusReporter in Filestream has been created for branch 8.19 but encountered conflicts
• #48077 [9.1](backport #48075) Remove direct access to v2.Context.StatusReporter in Filestream has been created for branch 9.1 but encountered conflicts
• #48078 [9.2](backport #48075) Remove direct access to v2.Context.StatusReporter in Filestream has been created for branch 9.2