Advanced Many-to-Many (Object) Relations: Support opening assigned element via double-click

[BlackbitDevs]

In editing panel, for non-advanced many-to-many (object) relations it is possible since a long time to open the referenced element via double click. For advanced many-to-many (object) relations this does currently not work. This PR adds this feature: When you double-click a column which is no meta column for the relation, the assigned element gets opened.

Steps to reproduce:

1. Create data object class with an advanced many-to-many object relation, set allowed class to the class itself, add a meta / custom field meta
2. Create object of this class
3. Create another object of this class
4. Open object from 3. and assign the object from 2. to the relation
5. Double-click a cell on the relation table except the meta column meta

With PR: Object from 2. will open.
Without PR: Nothing happens.

Have used target branch 1.7 because imho it is a UX bug. If you disagree and favor to put it into 2.x, also fine for me.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[mcop1]

@BlackbitDevs could you please rebase it to the 2.0 bugfix branch? Thank you!

[mcop1]

@BlackbitDevs could you please rebase it to the 2.0 bugfix branch? Thank you!

Never mind, thanks for the pr :)