fix(debugging): isDefined implementation [backport #15643 to 3.19]

[P403n1x87]

Backport 4d1b76c from #15643 to 3.19.

Description

We fix the implementation of the isDefined operation to accept an arbitrary expression that is evaluated within the scope of a proxy function. This is used to validate whether a certain expression would evaluate to a value without errors.

[github-actions]

CODEOWNERS have been resolved as:

releasenotes/notes/fix-debugger-el-isdefined-1c6b39c719c8888c.yaml      @DataDog/apm-python
ddtrace/debugging/_expressions.py                                       @DataDog/debugger-python
tests/debugging/test_expressions.py                                     @DataDog/debugger-python

[github-actions]

Bootstrap import analysis

Comparison of import times between this PR and base.

Summary

The average import time from this PR is: 245 ± 3 ms.

The average import time from base is: 247 ± 2 ms.

The import time difference between this PR and base is: -1.4 ± 0.1 ms.

Import time breakdown

The following import paths have shrunk:

ddtrace.auto 1.918 ms (0.78%)

ddtrace.bootstrap.sitecustomize 1.239 ms (0.50%)

ddtrace.bootstrap.preload 1.239 ms (0.50%)

ddtrace.internal.remoteconfig.client 0.612 ms (0.25%)

ddtrace 0.679 ms (0.28%)

ddtrace.internal._unpatched 0.029 ms (0.01%)

json 0.029 ms (0.01%)

json.decoder 0.029 ms (0.01%)

re 0.029 ms (0.01%)

enum 0.029 ms (0.01%)

types 0.029 ms (0.01%)