fix(symbolicator): use requests implementation instead of abstract class

[oioki]

Fixes this issue:

>>> from sentry.lang.native.sources import get_gcp_token
>>> t = get_gcp_token(client_email)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/.venv/lib/python3.13/site-packages/cachetools/__init__.py", line 702, in wrapper
    v = func(*args, **kwargs)
  File "/usr/src/sentry/src/sentry/lang/native/sources.py", line 630, in get_gcp_token
    target_credentials.refresh(Request())
                               ~~~~~~~^^
TypeError: Can't instantiate abstract class Request without an implementation for abstract method '__call__'

We need to use requests implementation instead of abstract class

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

⚠️ Parser warning

The parser emitted a warning. Please review your JUnit XML file:

Warning while parsing testcase attributes: Limit of string is 1000 chars, for name, we got 2083 at 1:156310 in /home/runner/work/sentry/sentry/.artifacts/pytest.junit.xml

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #92092      +/-   ##
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+ Coverage   84.08%   87.87%   +3.79%     
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  Files       10170    10172       +2     
  Lines      582941   582963      +22     
  Branches    22603    22603              
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+ Hits       490140   512294   +22154     
+ Misses      92348    70216   -22132     
  Partials      453      453