Hide stay logged in checkbox when flow authentication is used

[juliusknorr]

Fix for #7234

[codecov]

Codecov Report

Merging #7590 into master will decrease coverage by <.01%.
The diff coverage is 100%.

@@ Coverage Diff @@## master #7590 +/- ##
============================================
- Coverage 51.17% 51.16% -0.01% - Complexity 24886 24887 +1 
============================================
Files 1602 1602 Lines 94752 94753 +1 Branches 1368 1368 ============================================
- Hits 48485 48482 -3 - Misses 46267 46271 +4

Impacted Files	Coverage Δ	Complexity Δ
core/templates/login.php	0% <ø> (ø)	0 <0> (ø)	⬇️
core/Controller/LoginController.php	78.72% <100%> (+0.86%)	39 <0> (+1)	⬆️
lib/private/Security/CertificateManager.php	91.08% <0%> (-1%)	39% <0%> (ø)
core/js/js.js	62.98% <0%> (-0.57%)	0% <0%> (ø)
apps/files_trashbin/lib/Trashbin.php	72.28% <0%> (-0.25%)	136% <0%> (ø)
lib/private/Server.php	81.55% <0%> (+0.11%)	134% <0%> (ø)	⬇️
apps/files_trashbin/lib/Expiration.php	91.93% <0%> (+1.61%)	29% <0%> (ø)	⬇️

[MorrisJobke]

Tested and works 👍