fix: respect timeout setting in grpc method calls

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 83.33333% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 92.02%. Comparing base (d8e10c7) to head (f7285f0). Report is 13 commits behind head on main.

Files	Patch %	Lines
...src/openfeature/contrib/provider/flagd/provider.py	83.33%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #60 +/- ## ========================================== + Coverage 90.55% 92.02% +1.46% ========================================== Files 8 8 Lines 180 188 +8 ========================================== + Hits 163 173 +10 + Misses 17 15 -2 ``` | [Flag](https://app.codecov.io/gh/open-feature/python-sdk-contrib/pull/60/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-feature) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/open-feature/python-sdk-contrib/pull/60/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-feature) | `92.02% <83.33%> (+1.46%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-feature#carryforward-flags-in-the-pull-request-comment) to find out more.

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