Fix the bug: deploy key with write access can not push (#19010) (#19182)

Backport #19010

Use DeployKeyID to replace the IsDeployKey, then CanWriteCode uses the DeployKeyID to check the write permission.

Fix #19009

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

modules/private/serv.go

@@ -46,9 +46,9 @@ func ServNoCommand(ctx context.Context, keyID int64) (*asymkey_model.PublicKey,
 // ServCommandResults are the results of a call to the private route serv
 type ServCommandResults struct {
 	IsWiki      bool
-	IsDeployKey bool
-	KeyID       int64
-	KeyName     string
+	DeployKeyID int64
+	KeyID       int64  // public key
+	KeyName     string // this field is ambiguous, it can be the name of DeployKey, or the name of the PublicKey
 	UserName    string
 	UserEmail   string
 	UserID      int64