Speech Viewer: Do not update the speech text when the mouse is on the `TextCtrl` (#15953)
Fixes #15952
Summary of the issue:
The text is updated when the mouse moves on the Speech Viewer
Description of user facing changes
When the mouse is in TextCtrl, the voice text is no longer updated
Description of development approach
Add a condition to check whether the mouse is inside the TextCtrl when determining whether to update the text