We were linting against usages of `fdescribe` and `fit` by referencing the `no-jasmine-focus` rule which isn't installed, causing tslint to log the following:
```
Could not find implementations for the following rules specified in the configuration:
no-jasmine-focus
Try upgrading TSLint and/or ensuring that you have all necessary custom rules installed.
If TSLint was recently upgraded, you may have old rules configured which need to be cleaned
```
These changes switch to using the built-in `ban` rule.
PR Close#42415
Kristiyan Kostadinov
Pete Bacon Darwin
Joey Perrott
Jason Aden