infra: stop testing against the strawberryfields plugin

[math411]

Issue #, if available:

Description of changes:
stop testing against the strawberryfields plugin

Braket is not actively supporting development on this plugin. Removing from workflows.

Testing done:

Merge Checklist

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General

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• I used the commit message format described in CONTRIBUTING
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Tests

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[codecov]

Codecov Report

Merging #579 (e3f8421) into main (a6093b4) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              main      #579   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          118       118           
  Lines         7616      7616           
  Branches      1110      1110           
=========================================
  Hits          7616      7616