Stop appending templates - Temporary fix

What does this MR do?

This is the temporary fix for #23315 (moved). This stops the templates appending to any existing text.

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Temporary fix for #23315 (moved).

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Mentioned in issue #23315 (moved)

Reassigned to @alfredo1

Milestone changed to %8.14

Milestone changed to %8.13

Status changed to merged

Mentioned in commit 739cb052

Mentioned in issue #23656 (closed)

Picked into 8-13-stable, will go into 8.13.1.

Removed ~149423 label

Mentioned in commit 0778461d

mentioned in issue gitlab#6631