Do not use lower tag names to find releases/tags (#29261) (#29262)

Backport #29261.

Fix #26090, see
https://github.com/go-gitea/gitea/issues/26090#issuecomment-1952013206

Since `TagName` stores the original tag name and `LowerTagName` stores
the lower tag name, it doesn't make sense to use lowercase tags as
`TagNames` in `FindReleasesOptions`.

5e72526da4/services/repository/push.go (L396-L397)

While the only other usage looks correct:

5e72526da4/routers/web/repo/repo.go (L416)

services/repository/push.go

@@ -315,12 +315,7 @@ func pushUpdateAddTags(ctx context.Context, repo *repo_model.Repository, gitRepo
 		return nil
 	}
 
-	lowerTags := make([]string, 0, len(tags))
-	for _, tag := range tags {
-		lowerTags = append(lowerTags, strings.ToLower(tag))
-	}
-
-	releases, err := repo_model.GetReleasesByRepoIDAndNames(ctx, repo.ID, lowerTags)
+	releases, err := repo_model.GetReleasesByRepoIDAndNames(ctx, repo.ID, tags)
 	if err != nil {
 		return fmt.Errorf("GetReleasesByRepoIDAndNames: %w", err)
 	}
@@ -329,6 +324,11 @@ func pushUpdateAddTags(ctx context.Context, repo *repo_model.Repository, gitRepo
 		relMap[rel.LowerTagName] = rel
 	}
 
+	lowerTags := make([]string, 0, len(tags))
+	for _, tag := range tags {
+		lowerTags = append(lowerTags, strings.ToLower(tag))
+	}
+
 	newReleases := make([]*repo_model.Release, 0, len(lowerTags)-len(relMap))
 
 	emailToUser := make(map[string]*user_model.User)