Revert "Support SAML authentication (#25165)" (#29358)

This reverts #25165 (5bb8d1924d), as there
was a chance some important reviews got missed.

so after reverting this patch it will be resubmitted for reviewing again

https://github.com/go-gitea/gitea/pull/25165#issuecomment-1960670242

temporary Open #5512 again

web_src/js/index.js

@@ -23,10 +23,7 @@ import {initFindFileInRepo} from './features/repo-findfile.js';
 import {initCommentContent, initMarkupContent} from './markup/content.js';
 import {initPdfViewer} from './render/pdf.js';
 
-import {
-  initUserAuthOauth2,
-  initUserAuthSAML
-} from './features/user-auth.js';
+import {initUserAuthOauth2} from './features/user-auth.js';
 import {
   initRepoIssueDue,
   initRepoIssueReferenceRepositorySearch,
@@ -184,7 +181,6 @@ onDomReady(() => {
   initCaptcha();
 
   initUserAuthOauth2();
-  initUserAuthSAML();
   initUserAuthWebAuthn();
   initUserAuthWebAuthnRegister();
   initUserSettings();