Major regressions in BetterLineEdit and BetterTextEdit

[MewPurPur]

• ~~Clicking outside does not unfocus them.~~
• ~~Unfocusing fields does not cause them to update their value.~~
• LineEdits in command fields now unfocus when you move your cursor outside of its horizontal strip.
• A focused LineEdit doesn't get all of its text selected until an input event happens somewhere (happens when grab_focus() is called from code, for example in the built-in file dialog)

The first three are crucial to fix before alpha 4.