ReaderFooter: Cleanup some more messy dimensions handling

[NiLuJe]

Some stuff was still hacked on manually instead of trusting the widget system to do things right, which it does, if you update the right stuff at the right time the right way ;). This Is The Way.

Fix #6893 (and address #6878 (comment), because it was indeed redundant ^^).

Includes a bonus fix for a number of settings not being applied immediately in PDFs.

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This change is 

[poire-z]

Looks alright.

[Frenzie]

Looks fine, let me know if you want me to test though. ;-)

[poire-z]

Btw, @NiLuJe Footer Master, regarding #6885 (comment) :

In ReaderCropping:onPageCrop(), we backup a lot of settings to reset the view dimension to what's available above the bottom buttons.
Except that ReaderView (I guess) will still add (or remove, depending on how you look at it) the space taken by the footer:

If I hide the footer before launching that crop dialog, there is not this bottom grey blank area.

Is there a canonical way to check the footer is visible and hide it if it is (and later unhide it so we get back the footer exactly as it was) I could do in the part where we backup the original dimensions?

[NiLuJe]

@poire-z: You can check the non-ReaderFooter bits of #6830 for how the check (should) work.

Actually toggling it for real might be a bit trickier, though, because I don't think we have a direct way to do that: the tap handler cycles through modes. Might be able to store/set to 0/restore the mode manually and then call a full redraw (the various ways to do that were discussed a few days ago in a PR about a thingy not doing it or... something :D), though?

[NiLuJe]

@Frenzie: I think I checked the usual corner-cases, but, by all means ;).

[poire-z]

You can check the non-ReaderFooter bits of #6830 for how the check (should) work.
Actually toggling it for real might be a bit trickier, though

Thanks. Actually, I don't really need to toggle it... I just need to lie/tell ReaderView it's not visible :)

    -- backup original footer visibility
    self.orig_view_footer_visibility = self.view.footer_visible
    self.view.footer_visible = false

works for me!

[NiLuJe]

And just fixed a "slightly" older bug (mine ;p) so that toggling some stuff (mainly, the progress bar) in the settings actually repaints stuff immediately and properly in ReaderPaging.

(The old logic was relying on a CRe only chain of events for a bit of refresh optimization).

EDIT: Okay, looking at rg -F 'refreshFooter(true, true)', quite a bit more settings that just toggling the progress bar ;p.

[Frenzie]

@NiLuJe

I think I checked the usual corner-cases

And there's a lot of 'em too. Nothing obviously wrong.