Qt/WatchWidget: Don't update if not paused.

[AdmiralCurtiss]

This is a workaround for https://bugs.dolphin-emu.org/issues/13190.

There's definitely a better way to solve this but I'm really unsure what the proper way to deal with it is, so this should at least resolve the pseudo-infinite-loop in the meantime.

[JosJuice]

Is it fine to leave the table as it is when not paused, or should we clear it or something to make it clear to the user that the values are not up to date?

LGTM other than that.

[AdmiralCurtiss]

Probably better like this?

[JosJuice]

I just hope this won't make people think their watches have been deleted... I don't know, though. I'll leave the decision to someone who uses the debugging UI more than me.

[Pokechu22]

I don't think clearing the table is a good approach. It'd be better to gray out the values (perhaps using setDisabled) but leave the addresses and labels visible.

This also introduces a minor inconsistency: when the watch widget first appears, it has 0 rows, but after starting and then pausing a game, it gains 1 blank row (which is usable for creating new watches). Before, the 1 blank row was always visible (even when emulation hadn't started - though also you can use that blank row to create new watches when emulation hasn't started even though the menu options are disabled... it's fairly jank).

[AdmiralCurtiss]

Yes, this entire watch widget is super janky... feel free to fix it, but that wasn't my goal, I just wanted to stop Dolphin freezing and/or lagging when it's open.

[Pokechu22]

Now before the game starts, it looks like this:

which is really jank looking. That can probably be solved by moving the setHorizontalHeaderLabels call into CreateWidgets, and using clearContents() instead of clear(). (The empty row could also be created in CreateWidgets by duplicating this code there.)

This does fix the infinite loop though.

[AdmiralCurtiss]

There, yeah that's definitely better.

[Pokechu22]

Looks good enough to me.

There are still a few oddities:

• The "address" field doesn't get greyed out properly because we use a special brush for it to turn it red if it's not a valid address:
  
  I'm not sure how to properly combine disabled and custom brushes, and we might want to adjust the logic for this anyways in the future.
• The watch table doesn't get cleared when stopping emulation.

These don't need to be addressed now, and can be fixed in a future PR that makes other changes to the watch widget.

[AdmiralCurtiss]

The watch table doesn't get cleared when stopping emulation.

Honestly it probably should actually remain saved across sessions (at least for the same game)! But yeah, that's probably a more significant change.