Any mouse button can be used to select entries in the "Add Realm" screen

The Bug:

Any mouse button can be used to select entries in the "Add Realm" screen.

26.4 Snapshot 4 changed the world, server, and language lists to only react to the left mouse button (MC-309335), and 26.4 Snapshot 5 did the same for the statistics menu (MC-312640). The other Realms lists, such as the Realms list, the invite codes list, the preferred region list, and the world template list, also only react to the left mouse button, but this list was missed, therefore introducing an inconsistency.

Steps to Reproduce:

1. Click the "Minecraft Realms" button on the title screen, and then click the "Add Realm" button.

2. Right-click or middle-click the "A better way to play together" entry.

3. Observe if the entry is selected and a white outline appears around it.

Observed Behavior:

Entries in the "Add Realm" screen can be selected with non-left mouse buttons.

Expected Behavior:

Entries in the "Add Realm" screen would only be selected with the left mouse button.