[INLONG-11455][Sort] Only one OpenTelemetryAppender should be registered

[qy-liuhuo]

Fixes #11455

Motivation

Only one OpenTelemetryAppender should be registered

Modifications

Added duplicate registration judgment to the install and uninstall functions, and use synchronized locks to ensure concurrency safety.

Furthermore, since users may set different logging levels, force log messages to be appended on successful installs and uninstalls to ensure successful reporting at any logging level. This also makes it easier to write unit tests to check that the logging reports are working.

before:
LOG.info("OpenTelemetryLogger installed");

now:
otelAppender.append(
                    new Log4jLogEvent.Builder()
                        .setLevel(Level.INFO)
                        .setMessage(new SimpleMessage("OpenTelemetryLogger installed"))
                        .build());

Verifying this change

(Please pick either of the following options)

• This change is a trivial rework/code cleanup without any test coverage.

• This change is already covered by existing tests, such as:
  (please describe tests)

• This change added tests and can be verified as follows:

  (example:)

  • Added integration tests for end-to-end deployment with large payloads (10MB)
  • Extended integration test for recovery after broker failure

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)
• If a feature is not applicable for documentation, explain why?
• If a feature is not documented yet in this PR, please create a follow-up issue for adding the documentation

[XiaoYou201]

LGTM~