Fix touch problems with popup menus and edit shapes tool

• Popup menus summoned by touch now appear in the touched position, rather than at the (unrelated) cursor position.
• Edit shapes tool now works with touch painting, BUG:511594.

I verified that these backport to 5.2.

Test Plan

1. Enable touch drawing. Create a vector layer. Lay down a path with the bezier curve tool. Switch to the edit shapes tool and edit the shape via touch. Observe that it works now, rather than just making blue rectangles.
2. Disable touch drawing. Switch to the selection tool. Touch the canvas with one finger. Observe that the selection actions popup menu appears where you touched, rather than where your cursor last was.

Formalities Checklist

• I confirmed this builds.
• I confirmed Krita ran and the relevant functions work.
• I tested the relevant unit tests and can confirm they are not broken. (If not possible, don't hesitate to ask for help!)
• I made sure my commits build individually and have good descriptions as per KDE guidelines.
• I made sure my code conforms to the standards set in the HACKING file.
• I can confirm the code is licensed and attributed appropriately, and that unattributed code is mine, as per KDE Licensing Policy.
• Does the patch add a user-visible feature? If yes, is there a documentation MR ready for it at Krita Documentation Repository?

Reminder: the reviewer is responsible for merging the patch, this is to ensure at the least two people can build the patch. In case a patch breaks the build, both the author and the reviewer should be contacted to fix the build. If this is not possible, the commits shall be reverted, and a notification with the reasoning and any relevant logs shall be sent to the mailing list, kimageshop@kde.org.