Add confirmation popup for tree version convert

[Peechey]

Description of the problem being solved:

Improvements to version convert: allow users the choice to replace or backup current spec before conversion. Works/looks better with pr 6365 but I want to keep them separate in case we don't add this.

Steps taken to verify a working solution:

• Convert should replace the current spec and active spec should be the converted spec
• Copy + Convert should have both with active spec => converted spec
• Cancel do be canceling
• Outside of the popup, Convert to latest should still work and show the success popup

After screenshot: