Support getting last commit message using contents-ext API (#34904)

Fix #34870
Fix #34929

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

tests/integration/api_repo_file_create_test.go

@@ -19,6 +19,7 @@ import (
 	"code.gitea.io/gitea/modules/gitrepo"
 	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
+	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/services/context"
 
 	"github.com/stretchr/testify/assert"
@@ -52,8 +53,8 @@ func getCreateFileOptions() api.CreateFileOptions {
 func normalizeFileContentResponseCommitTime(c *api.ContentsResponse) {
 	// decoded JSON response may contain different timezone from the one parsed by git commit
 	// so we need to normalize the time to UTC to make "assert.Equal" pass
-	c.LastCommitterDate = c.LastCommitterDate.UTC()
-	c.LastAuthorDate = c.LastAuthorDate.UTC()
+	c.LastCommitterDate = util.ToPointer(c.LastCommitterDate.UTC())
+	c.LastAuthorDate = util.ToPointer(c.LastAuthorDate.UTC())
 }
 
 type apiFileResponseInfo struct {
@@ -74,9 +75,9 @@ func getExpectedFileResponseForCreate(info apiFileResponseInfo) *api.FileRespons
 			Name:              path.Base(info.treePath),
 			Path:              info.treePath,
 			SHA:               sha,
-			LastCommitSHA:     info.lastCommitSHA,
-			LastCommitterDate: info.lastCommitterWhen,
-			LastAuthorDate:    info.lastAuthorWhen,
+			LastCommitSHA:     util.ToPointer(info.lastCommitSHA),
+			LastCommitterDate: util.ToPointer(info.lastCommitterWhen),
+			LastAuthorDate:    util.ToPointer(info.lastAuthorWhen),
 			Size:              16,
 			Type:              "file",
 			Encoding:          &encoding,