Explicitly mark invisible widgets in GtkBuilder files.

GTK+ 4 has switched the default from invisible to visible - these widgets
would all suddenly appear if GTK+ 4 was used.

The widgets without a visible property were found programatically.
11 jobs for gtkbuilder-explicit-hide in 5 minutes and 54 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Build
passed #144847
build

00:01:57

 
  Test
passed #144849
asan

00:02:06

passed #144848
test

00:01:50

 
  Manual
manual #144854
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armv8
manual #144850
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flatpak
manual #144853
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msan
manual #144855
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ppc64le
manual #144851
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tsan
manual #144852
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ubsan
 
  Review
manual #144856
allowed to fail manual
review
manual #144857
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