Minor tabs cleanup toward fixing dev/core#2215

[colemanw]

Overview

A little code cleanup as a precursor to fixing https://lab.civicrm.org/dev/core/-/issues/2215

Before

1. Variable CRM.tabSettings.active was overwritten when initializing tabs
2. Campaign dashboard page initialized tabs again on every tab load.

After

1. Avoid overwriting CRM.tabSettings.active by cloning the variable rather than copying by reference
2. Initialize tabs only once on the Campaign dashboard

[civibot]

(Standard links)

• If this is your first pull-request for CiviCRM, please browse CONTRIBUTING.md for information about the development and testing processes.
• If you are reviewing this pull-request, you may wish to consult the test sites and the Review Standards (long template, short template).

[mattwire]

Tested contact summary, configure event, message templates. All working as before.

[colemanw]

Thanks @mattwire