chore: QoL improvements to tests (#7917)

- Use mock helper functions, instead of home-brew solutions.
- Disable cron jobs that are not important to be run during integration tests and might even interfere.
- Avoid sleeping unnecessary, if there's some requirement then sleep or retry until that requirement is met.
- Avoid trying to deliver webhooks that will always result in a failure.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7917
Reviewed-by: Michael Kriese <michael.kriese@gmx.de>
Co-authored-by: Gusted <postmaster@gusted.xyz>
Co-committed-by: Gusted <postmaster@gusted.xyz>

services/webhook/webhook_test.go

@@ -14,6 +14,7 @@ import (
 	webhook_model "forgejo.org/models/webhook"
 	"forgejo.org/modules/setting"
 	api "forgejo.org/modules/structs"
+	"forgejo.org/modules/test"
 	webhook_module "forgejo.org/modules/webhook"
 	"forgejo.org/services/convert"
 
@@ -104,7 +105,8 @@ func TestPrepareWebhooksBranchFilterNoMatch(t *testing.T) {
 
 func TestWebhookUserMail(t *testing.T) {
 	require.NoError(t, unittest.PrepareTestDatabase())
-	setting.Service.NoReplyAddress = "no-reply.com"
+	defer test.MockVariableValue(&setting.Service.NoReplyAddress, "no-reply.com")()
+
 	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
 	assert.Equal(t, user.GetPlaceholderEmail(), convert.ToUser(db.DefaultContext, user, nil).Email)
 	assert.Equal(t, user.Email, convert.ToUser(db.DefaultContext, user, user).Email)