Fix page and missing return on unadopted repos API (#18848)

* Fix page and missing return on unadopted repos API

Page must be 1 if it's not specified and it should return after sending an internal server error.

* Allow ignore pages

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

integrations/api_repo_test.go

@@ -468,7 +468,6 @@ func TestAPIRepoTransfer(t *testing.T) {
 		expectedStatus int
 	}{
 		// Disclaimer for test story: "user1" is an admin, "user2" is normal user and part of in owner team of org "user3"
-
 		// Transfer to a user with teams in another org should fail
 		{ctxUserID: 1, newOwner: "user3", teams: &[]int64{5}, expectedStatus: http.StatusForbidden},
 		// Transfer to a user with non-existent team IDs should fail