devel/qt6-base: Support setting thread names

Thread names can now be set by calling QObject::setObjectName() before
starting the thread. Previously, the thread name would be the class name
of the runtime type of the thread object.

PR: 290676
MFH: 2025Q4
(cherry picked from commit 896ba2348dd148009fc3a62a3e0c23608028832f)