Deduepe - Fix form buttons (again)

[colemanw]

Overview

Yet another fix for the dedupe form buttons. This feels like a duplicate of the duplicate fix in #23035 but hopefully fixed for real this time and we can stop duplicating these duplicate button fixes!

Before

See dev/core#3421
Also see dev/core#3135
And the original cause: a6f2a80

After

With this patch in place I've tried out all the buttons in all the different contexts and they all seem to be behaving correctly:

Search Mode

• ✔️ Clicking merge from advanced search action redirects to the contact
• ✔️ Clicking merge from search kit modal gives success msg and closes the modal

Dedupe Find Mode

• ✔️ Clicking "Merge and View Result" takes you to the contact record.
• ✔️ Clicking "Merge and go to listing" takes you back to the list of duplicates.
• ✔️ Clicking "Merge and go to next pair" takes you to the next set of duplicates.

Technical Details

The problem is that the form is used in different contexts and it's a complex multi-step form, but it can also be used as a one-step form via search and it can also be loaded in an ajax modal. So getting the buttons to behave in every context is tricky.

[civibot]

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