[GITEA] Make atomic ssh keys replacement robust

- After stumbling upon https://github.com/golang/go/issues/22397 and
reading the implementations I realized that Forgejo code doesn't have
`Sync()` and it doesn't properly error handle the `Close` function.
- (likely) Resolves https://codeberg.org/forgejo/forgejo/issues/1446

(cherry picked from commit 0efcb334c2)
(cherry picked from commit 04ef02c0dd)
(cherry picked from commit 85f2065c9b)
(cherry picked from commit 8d36b5cce6)
(cherry picked from commit 0f406dc4d2)
(cherry picked from commit 347a2e7372)
(cherry picked from commit f6c04d6b86)

models/asymkey/ssh_key_authorized_principals.go

@@ -92,7 +92,12 @@ func RewriteAllPrincipalKeys(ctx context.Context) error {
 		return err
 	}
 
-	t.Close()
+	if err := t.Sync(); err != nil {
+		return err
+	}
+	if err := t.Close(); err != nil {
+		return err
+	}
 	return util.Rename(tmpPath, fPath)
 }