fix: when using ' in strings, fluttium is crashing with "Error: String starting with ' must end with '."

[Verry]

Description
I checked for the text "I'M FINE, TAKE ME TO THE REGISTRATION" using - expectVisible: "I'M FINE, LOGIN ANONYMOUSLY"and my tests crashed and fluttium --watch wasn't able to restart the tests anymore. I had to rerun the fluttium test my_flow.yaml --watch command in order to receive the following error message:

.fluttium_driver.dart:35:63: Error: String starting with ' must end with '.
      await tester.expectVisible(r'I'M FINE, LOGIN ANONYMOUSLY');

Steps To Reproduce

1. Add - expectVisible: "I'M FINE, LOGIN ANONYMOUSLY" to my_flow.yaml
2. Run fluttium test my_flow.yaml --watch
3. Try to rerun tests with "r" command - shouldn't work
4. Repeat 2
5. See error message appearing

Expected Behavior
Fluttium should be able to handle texts including the ' character.

Screenshots

[Jochum van der Ploeg]

This should be easy fixed by sanitising all the string values! I'll tackle this later today.

Thank you for the bug report <3