fix: Force stream selection in tests

[edgarrmondragon]

Following #1672, tests (both --test and automatic pytest) fail to force selection of streams marked with selected_by_default = False. This PR addresses that.

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📚 Documentation preview 📚: https://meltano-sdk--1698.org.readthedocs.build/en/1698/

[codecov]

Codecov Report

Merging #1698 (3034013) into main (5a5f43a) will increase coverage by 0.02%.
The diff coverage is 100.00%.

❗ Current head 3034013 differs from pull request most recent head 03d2f1c. Consider uploading reports for the commit 03d2f1c to get more accurate results

@@            Coverage Diff             @@
##             main    #1698      +/-   ##
==========================================
+ Coverage   85.69%   85.72%   +0.02%     
==========================================
  Files          59       59              
  Lines        4937     4896      -41     
  Branches      809      803       -6     
==========================================
- Hits         4231     4197      -34     
+ Misses        505      497       -8     
- Partials      201      202       +1     

Impacted Files	Coverage Δ
singer_sdk/streams/core.py	83.33% <100.00%> (+0.11%)	⬆️
singer_sdk/tap_base.py	79.18% <100.00%> (+5.09%)	⬆️

... and 7 files with indirect coverage changes

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