chore(llmobs): remove public notice of submit_evaluation_for (#11997)

We're holding off on a public release of joining by tag for evaluation
metrics. This PR removes the deprecation notice for `submit_evaluation`,
the predecessor to `submit_evaluation_for`, and removes the release note
for `submit_evaluation_for`.

We don't revert the entire original PR because:
- any urgent customers blocked on joining by tag can use
`submit_evaluation_for` in an "early access" mode
- we still want to keep the changes that updates the eval metric writer
to write to the `v2` eval metric endpoint

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

---------

Co-authored-by: lievan <[email protected]>

Author: lievan

ddtrace/llmobs/_llmobs.py

@@ -28,7 +28,6 @@
 from ddtrace.internal.service import ServiceStatusError
 from ddtrace.internal.telemetry import telemetry_writer
 from ddtrace.internal.telemetry.constants import TELEMETRY_APM_PRODUCT
-from ddtrace.internal.utils.deprecations import DDTraceDeprecationWarning
 from ddtrace.internal.utils.formats import asbool
 from ddtrace.internal.utils.formats import parse_tags_str
 from ddtrace.llmobs import _constants as constants
@@ -68,7 +67,6 @@
 from ddtrace.llmobs.utils import ExportedLLMObsSpan
 from ddtrace.llmobs.utils import Messages
 from ddtrace.propagation.http import HTTPPropagator
-from ddtrace.vendor.debtcollector import deprecate
 
 
 log = get_logger(__name__)
@@ -1053,13 +1051,6 @@ def submit_evaluation(
         timestamp_ms: Optional[int] = None,
         metadata: Optional[Dict[str, object]] = None,
     ) -> None:
-        deprecate(
-            "Using `LLMObs.submit_evaluation` is deprecated",
-            message="Please use `LLMObs.submit_evaluation_for` instead.",
-            removal_version="3.0.0",
-            category=DDTraceDeprecationWarning,
-        )
-
         """
         Submits a custom evaluation metric for a given span ID and trace ID.