Use gitrepo.GetTreePathLatestCommit to get file lastest commit instead from latest commit cache (#32987)

The latest commit cache is currently used only for listing tree files.
However, a cold start may take longer than directly invoking the Git
command. This PR addresses the issue of slow response times when
accessing raw files, improving performance in such scenarios.

```log
gitea.log:105521:2024/12/23 08:22:18 ...eb/routing/logger.go:68:func1() [W] router: slow      GET /xxxx/xxxxxx/raw/commit/xxxxxxxxxxxxxxxxxxxxxxxxxxx/.editorconfig for 172.18.0.5:53252, elapsed 3526.8ms @ repo/download.go:117(repo.SingleDownload)
```

2 files changed, 9 insertions, 21 deletions

diff --git a/routers/api/v1/repo/file.go b/routers/api/v1/repo/file.go
index 6591b9a752..8a4f78a3d7 100644
--- a/routers/api/v1/repo/file.go
+++ b/routers/api/v1/repo/file.go
@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"path"
 	"strings"
 	"time"
 
@@ -242,19 +241,14 @@ func getBlobForEntry(ctx *context.APIContext) (blob *git.Blob, entry *git.TreeEn
 		return nil, nil, nil
 	}
 
-	info, _, err := git.Entries([]*git.TreeEntry{entry}).GetCommitsInfo(ctx, ctx.Repo.Commit, path.Dir("/" + ctx.Repo.TreePath)[1:])
+	latestCommit, err := ctx.Repo.GitRepo.GetTreePathLatestCommit(ctx.Repo.Commit.ID.String(), ctx.Repo.TreePath)
 	if err != nil {
-		ctx.Error(http.StatusInternalServerError, "GetCommitsInfo", err)
+		ctx.Error(http.StatusInternalServerError, "GetTreePathLatestCommit", err)
 		return nil, nil, nil
 	}
+	when := &latestCommit.Committer.When
 
-	if len(info) == 1 {
-		// Not Modified
-		lastModified = &info[0].Commit.Committer.When
-	}
-	blob = entry.Blob()
-
-	return blob, entry, lastModified
+	return entry.Blob(), entry, when
 }
 
 // GetArchive get archive of a repository
diff --git a/routers/web/repo/download.go b/routers/web/repo/download.go
index 1ed907b2f9..cb1163c70b 100644
--- a/routers/web/repo/download.go
+++ b/routers/web/repo/download.go
@@ -5,7 +5,6 @@
 package repo
 
 import (
-	"path"
 	"time"
 
 	git_model "code.gitea.io/gitea/models/git"
@@ -82,7 +81,7 @@ func ServeBlobOrLFS(ctx *context.Context, blob *git.Blob, lastModified *time.Tim
 	return common.ServeBlob(ctx.Base, ctx.Repo.TreePath, blob, lastModified)
 }
 
-func getBlobForEntry(ctx *context.Context) (blob *git.Blob, lastModified *time.Time) {
+func getBlobForEntry(ctx *context.Context) (*git.Blob, *time.Time) {
 	entry, err := ctx.Repo.Commit.GetTreeEntryByPath(ctx.Repo.TreePath)
 	if err != nil {
 		if git.IsErrNotExist(err) {
@@ -98,19 +97,14 @@ func getBlobForEntry(ctx *context.Context) (blob *git.Blob, lastModified *time.T
 		return nil, nil
 	}
 
-	info, _, err := git.Entries([]*git.TreeEntry{entry}).GetCommitsInfo(ctx, ctx.Repo.Commit, path.Dir("/" + ctx.Repo.TreePath)[1:])
+	latestCommit, err := ctx.Repo.GitRepo.GetTreePathLatestCommit(ctx.Repo.Commit.ID.String(), ctx.Repo.TreePath)
 	if err != nil {
-		ctx.ServerError("GetCommitsInfo", err)
+		ctx.ServerError("GetTreePathLatestCommit", err)
 		return nil, nil
 	}
+	lastModified := &latestCommit.Committer.When
 
-	if len(info) == 1 {
-		// Not Modified
-		lastModified = &info[0].Commit.Committer.When
-	}
-	blob = entry.Blob()
-
-	return blob, lastModified
+	return entry.Blob(), lastModified
 }
 
 // SingleDownload download a file by repos path