Set `shell: bash` by default on all workflows #4943

Job	Run time
Diagnostic export (macos-latest, linked)	59s
Diagnostic export (windows-latest, linked)	2m 19s
Diagnostic export (ubuntu-latest, linked)	59s
Diagnostic export (windows-latest, nightly-latest)	2m 47s
Diagnostic export (macos-latest, nightly-latest)	58s
Diagnostic export (ubuntu-latest, nightly-latest)	1m 3s
	9m 5s

Provide feedback