Consider beam_services option when determining the expansion service type

[chamikaramj]

Cherry-picks #27345 to 2.49.0 release branch.

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[chamikaramj]

R: @Abacn

[github-actions]

Stopping reviewer notifications for this pull request: review requested by someone other than the bot, ceding control

[codecov]

Codecov Report

Merging #27353 (8b17f91) into release-2.49.0 (58639da) will increase coverage by 0.00%.
The diff coverage is 42.85%.

@@               Coverage Diff               @@
##           release-2.49.0   #27353   +/-   ##
===============================================
  Coverage           71.49%   71.50%           
===============================================
  Files                 858      858           
  Lines              104809   104813    +4     
===============================================
+ Hits                74938    74944    +6     
+ Misses              28323    28321    -2     
  Partials             1548     1548           

Flag	Coverage Δ
python	80.83% <42.85%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
sdks/python/apache_beam/transforms/external.py	75.66% <25.00%> (-0.42%)	⬇️
sdks/python/apache_beam/utils/subprocess_server.py	58.73% <66.66%> (ø)

... and 2 files with indirect coverage changes

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