applications: Make async file operations cancellable

The previous operations could crash if the panel was changed during an operation.
11 jobs for <span class="ref-name">applications-cancellable-file-operations</span> in 2 minutes and 49 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #250181
build

00:01:21

 
  Test
passed #250183
asan

00:01:27

passed #250182
test

00:00:44

 
  Manual
manual #250188
allowed to fail manual
armv8
manual #250184
allowed to fail manual
flatpak
manual #250187
allowed to fail manual
msan
manual #250189
allowed to fail manual
ppc64le
manual #250185
allowed to fail manual
tsan
manual #250186
allowed to fail manual
ubsan
 
  Review
manual #250190
allowed to fail manual
review
manual #250191
allowed to fail manual
stop_review