Ensure that 'Link to an entry' links to current site by default

[Alxmerino]

Description

This PR updates the link insertion behavior in CKEditor so that when adding a "Link to an entry," it defaults to linking to the current site, rather than the entry’s original site.

Current Behavior

• In Entry A on Site A:
  • Add a link by clicking "Link to an entry"
  • Select Entry B
  • Link is inserted into the CKEditor field
• When viewing Entry A on Site B and clicking the link, it navigates to Entry B on Site A

Expected Behavior

• Follow the same steps as above
• When viewing Entry A on Site B and clicking the link, it navigates to Entry B on Site B

Related Issues

• Internal links in "Translated for each site group" default link location #282