Create a new section in `i_create_a_node.js` Cypress step definition file for the `vet_center_mobile_vet_center` content type.

[ndouglas]

See #11493.

Acceptance Criteria

• A section has been created in i_create_a_node.js corresponding to the specified content type.
• A new test is added in content_type__<content_type>.feature utilizing the step definition to create and save a node of the specified content type.
• Tests pass reliably (run the specific content type's test in a loop 20 times without failure). This is probably most easily done by running a script like the following:

content_type=banner;
for i in $(seq 1 20); do
  echo "Running test # ${i}...";
  ./node_modules/.bin/cypress run --spec "tests/cypress/integration/behavioral/content_type__${content_type}.feature";
done;