Migrate to ESLint 9 (#10762)

* update ESLint related packages

* migrate to flat config format

* Fix prefer-const error

Fixes
'overrideLogoSize' is never reassigned. Use 'const' instead

* remove irrelevant eslint-disable comment

These comments came from a swizzled upstream
component but never did anything in our codebase.

ESLint 9 does not allow disable comments
for rules that are not registered.

* remove irrelevant eslint-disable comments

These were here because in the past we were applying
mocha lint rules to files which contained no tests

ESLint 9 now flags eslint-disable comments
that aren't doing anythings

* remove irrelevant eslint-disable comment

ESLint 9 now flags eslint-disable comments
that aren't doing anything

* there are no .tsx files in our code any more

* include .mjs files in linting and formatting

* update sort-class-members rule for openApi property

and update the handful of files violating it