fix: classify git failures on stderr, restrict migration failure detail (#39010)

Signed-off-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/git/gitcmd/error_test.go

@@ -17,8 +17,10 @@ func TestIsStderr(t *testing.T) {
 		{StderrUnknownRevisionOrPath, "fatal: ambiguous argument 'origin': unknown revision or path not in the working tree...."},
 		{StderrNoMergeBase, "fatal: origin/main..HEAD: no merge base...."},
 		{StderrFileNoEnoughLines, "fatal: file foo/bar has only 1 line"},
+		{StderrAuthenticationFailed, "Cloning into 'repo'...\r\nremote: Invalid username or token.\r\nfatal: Authentication failed for 'https://host/repo.git/'\r\n"},
 	}
 	for _, tc := range cases {
 		assert.True(t, IsStderr(&runStdError{stderr: tc.stderr}, tc.check), "stderr: %s", tc.stderr)
 	}
+	assert.False(t, IsStderr(&runStdError{stderr: "remote: fatal: Authentication failed for 'https://host/repo.git/'\n"}, StderrAuthenticationFailed))
 }