PYTHON-4463 Add authMechanism option to tests where needed (#1665)

(cherry picked from commit ca543d4)

Author: blink1073

test/connection_string/test/valid-options.json

@@ -40,7 +40,7 @@
     },
     {
       "description": "Colon in a key value pair",
-      "uri": "mongodb://example.com?authMechanismProperties=TOKEN_RESOURCE:mongodb://test-cluster",
+      "uri": "mongodb://example.com/?authMechanism=MONGODB-OIDC&authMechanismProperties=TOKEN_RESOURCE:mongodb://test-cluster",
       "valid": true,
       "warning": false,
       "hosts": [

test/connection_string/test/valid-warnings.json

@@ -96,13 +96,13 @@
     },
     {
       "description": "Comma in a key value pair causes a warning",
-      "uri": "mongodb://example.com?authMechanismProperties=TOKEN_RESOURCE:mongodb://host1%2Chost2",
+      "uri": "mongodb://localhost?authMechanism=MONGODB-OIDC&authMechanismProperties=TOKEN_RESOURCE:mongodb://host1%2Chost2",
       "valid": true,
       "warning": true,
       "hosts": [
         {
           "type": "hostname",
-          "host": "example.com",
+          "host": "localhost",
           "port": null
         }
       ],