MoveStrokeStrategy: Const Qualify Nodes and Remove Duplicate Header

I noticed that MoveStrokeStrategy::recursiveApplyNodes(KisNodeList nodes, Functor &&func) was copying a new KisNodeList for each function invocation.

recursiveApplyNodes() is called in 7 different places, including on init, cancel, and update, so we were creating a new KisNodeList many times during each Move.

Also, out of scope and unrelated: there was a duplicate header that I removed.

Test Plan

• Used Move tool with new and existing .kra projects
• Used Move tool with multiple layers
• Used Move tool with different selections

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.