Replace some TTRCs with RTRs

[KoBeWi]

Addresses #50650
TTRC was not needed in the cases there, as none of this is saved in the scene, so it won't be causing problems (🤞).
Not sure if doing changes in FileDialog is necessary, as it's probably not used in the editor, idk.
Also I used TTR not RTR, as the strings are automatically runtime-translated anyway.

This doesn't fully fix the issue, because titles are still not translated. But changing them to TTR() would re-introduce translated property bug, so not sure how to solve this.

[timothyqiu]

I think CI would fail because TTR is not defined in non-tools builds. FYI: It's removed in #59636.

[KoBeWi]

Hmm, RTR might break auto_translate property, by forcing translation. I'll have to check.

EDIT:
Ok auto_translate is only for custom strings, so it doesn't matter here.

[akien-mga]

This pretty much reverts #46735, no? Won't it reintroduce the issues that it was trying to fix? CC @fabriceci

[KoBeWi]

No, #39258 will not be re-introduced. The problem was that RTR was used on dialog title, which is saved to a property, hence the translated string was saved. This PR doesn't restore RTR in title. All other strings are not saved in scene, because they are texts of internal controls, so there won't be issue.

#46735 was mostly correct, but most of the added TTRCs weren't actually necessary.

[akien-mga]

Thanks!