Remove duplicated notify mail configuration on tests (#26912)

Extract from #22266

Co-authored-by: Giteabot <teabot@gitea.io>

tests/mssql.ini.tmpl

@@ -64,7 +64,6 @@ FROM = mssql-{{TEST_TYPE}}-test@gitea.io
 [service]
 REGISTER_EMAIL_CONFIRM            = false
 REGISTER_MANUAL_CONFIRM           = false
-ENABLE_NOTIFY_MAIL                = false
 DISABLE_REGISTRATION              = false
 ENABLE_CAPTCHA                    = false
 REQUIRE_SIGNIN_VIEW               = false

tests/mysql.ini.tmpl

@@ -64,7 +64,6 @@ FROM = mysql-{{TEST_TYPE}}-test@gitea.io
 [service]
 REGISTER_EMAIL_CONFIRM            = false
 REGISTER_MANUAL_CONFIRM           = false
-ENABLE_NOTIFY_MAIL                = false
 DISABLE_REGISTRATION              = false
 ENABLE_CAPTCHA                    = false
 REQUIRE_SIGNIN_VIEW               = false

tests/pgsql.ini.tmpl

@@ -65,7 +65,6 @@ FROM = pgsql-{{TEST_TYPE}}-test@gitea.io
 [service]
 REGISTER_EMAIL_CONFIRM            = false
 REGISTER_MANUAL_CONFIRM           = false
-ENABLE_NOTIFY_MAIL                = false
 DISABLE_REGISTRATION              = false
 ENABLE_CAPTCHA                    = false
 REQUIRE_SIGNIN_VIEW               = false