fix: wrap cmd in subshell to fix ::set-teamsfx-env not captured on Linux when script uses semicolons

[Copilot]

When cmd contains semicolons (common in YAML multi-line run: blocks), bash parses them as command separators — causing each echo to run standalone without the tee redirect. The temp file stays empty, parseSetOutputCommand returns {}, and no env vars are set.

Change

Wrap ${cmd} in a subshell so bash treats its entire content as one unit piped through tee:

- scriptContent = `#!/bin/bash\nset +e\n${cmd} 2>&1 | tee "${tempFile}"\nexit \${PIPESTATUS[0]}\n`;
+ scriptContent = `#!/bin/bash\nset +e\n( ${cmd} ) 2>&1 | tee "${tempFile}"\nexit \${PIPESTATUS[0]}\n`;

Only the Linux/bash path is affected; the PowerShell path already uses a & { ... } block for the same reason.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.32%. Comparing base (92c0382) to head (e3f357c).
⚠️ Report is 5 commits behind head on dev.

Additional details and impacted files

@@           Coverage Diff           @@
##              dev   #15818   +/-   ##
=======================================
  Coverage   93.32%   93.32%           
=======================================
  Files         587      587           
  Lines       37120    37120           
  Branches     6903     6960   +57     
=======================================
  Hits        34641    34641           
  Misses       1835     1835           
  Partials      644      644           

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