[modeler] Allow QGIS interaction while running an algorithm in the modeler

[ValentinBuira]

Description

This PR allow using QGIS while running an algorithm in the modeler

exemple.running.non.modal.webm

This work by :

• Allowing the execution algorithm dialog to be modal in a similar fashion to the execution from the toolbox

• Except only one algorithm execution dialog is allowed per model at the time. if the user hit run and a dialog is already existing it would recreate one
• If The dialog is already running, and only in this case, the user is prompted with a choice(see message box below) where :
  • Cancel -> do nothing and close with message box
  • Re Run algorithm -> cancel the existing dialog and recreate one
  • Show algorithm -> display the currently running algorithm

As the side effect this:

• Fix RuntimeError: wrapper C/C++ object of type AlgorithmDialog has been deleted.
  Previously if you closed the algorithm dialog using the close button or the close window while an algorithm was running, the QgsProcessingAlgRunnerTask task would have outlive the dialog leading to Runtime Error. Now the dialog have a long lifespan
• Fix "Point" input not working in Processing Modeller? #31969
• Fix "Draw on Canvas" option of "Create layer from extent" tool is not working when run under Graphical Modeler #49126

Funded by the QGIS user group Switzerland

[github-actions]

🪟 Windows Qt6 builds

Download Windows Qt6 builds of this PR for testing.
(Built from commit 7b8dbfb)

🍎 MacOS Qt6 builds

Download MacOS Qt6 builds of this PR for testing.
This app is not notarized, run sudo xattr -d com.apple.quarantine /Applications/QGIS*.app to avoid the warning
(Built from commit 7b8dbfb)

🪟 Windows builds

Download Windows builds of this PR for testing.
Debug symbols for this build are available here.
(Built from commit da24980)

[ValentinBuira]

I completely rework the PR to account for running a subset and as well make it way simpler in design.

Instead of a complicated watch if the model have changed, the dialog is re created each time.

If an algorithm is already running and only in this case, the user is asked
Cancel -> do nothing and close with message box
Re Run algorithm -> cancel the existing dialog and recreate one
Show algorithm -> display the currently running algorithm

I updated the PR description to reflect the latest changes.

[3nids]

can you explain in the docs the difference with isFinalized() (and potentially link them in the docs)