fix: consistant env name regex

[jayzhang]

https://msazure.visualstudio.com/Microsoft%20Teams%20Extensibility/_workitems/edit/28357001

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.51%. Comparing base (1742b3d) to head (4d89946).
Report is 3 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev   #11810      +/-   ##
==========================================
- Coverage   88.51%   88.51%   -0.01%     
==========================================
  Files         536      536              
  Lines       32894    32893       -1     
  Branches     6438     6486      +48     
==========================================
- Hits        29117    29116       -1     
  Misses       1809     1809              
  Partials     1968     1968              

Files	Coverage Δ
packages/fx-core/src/component/utils/envUtil.ts	89.05% <100.00%> (ø)

... and 1 file with indirect coverage changes