fix(di): use enum value for evaluate_at property

[P403n1x87]

We make sure that we get the value from the enum for the evaluate_at property so that proper validation and comparison can be performed. Currently, the timing value is stored as a plain string, whereas the logic that handles them expects one of the possible enum values, thus making the check fail always.

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
• The change includes or references documentation updates if necessary
• Backport labels are set (if applicable)

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 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

[github-actions[bot]]

CODEOWNERS have been resolved as:

releasenotes/notes/fix-span-decoration-probe-timing-dc4ce0664fa645b9.yaml  @DataDog/apm-python
ddtrace/debugging/_probe/remoteconfig.py                                @DataDog/debugger-python

[pr-commenter[bot]]

Benchmarks

Benchmark execution time: 2024-10-21 12:15:44

Comparing candidate commit 663dea13a79d4d4363c08a1d030d11af96668dfb in PR branch fix/span-decoration-probe-timing with baseline commit 6d8ee31ead0d76adc2d1516f0f2990c6dd71cb26 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 365 metrics, 53 unstable metrics.