Fix Trial invite members button showing with new nav

What does this MR do and why?

Fixes issue where invite member button doesn't appear in the trial alert on the new nav

Rely on global load of the invite modal javascript bits instead of individual loading on every page that needs it.

📓 The invite members modal testing wise was tightened up in !111976 (merged), so this change should have all applicable test coverage in that regard.

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Launch local GDK to simulate saas
2. Navigate to any group and project under the namespace owned by the signed-in user
3. Verify the Invite more members button shows.

Note: To skip setting up trial for a namespace locally, go to the file ee/app/helpers/ee/users/group_callouts_helper.rb and insert a new line as the first line in the show_unlimited_members_during_trial_alert? method with return true.

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.

Related to #413438 (closed)