Make `no-cond-assign` work for ternaries too

What rule do you want to change?

no-cond-assign

Does this change cause the rule to produce more or fewer warnings?

More warnings

How will the change be implemented? (New option, new default behavior, etc.)?

I guess new default?

Please provide some example code that this change will affect:

  const str = (x = 0) ? 'zero' : 'non-zero'

What does the rule currently do for this code?

No warnings are produced

What will the rule do after it’s changed?

Produce an “Unexpected assignment” warning for the condition of the ternary

[ljharb]

@fvictorio looks like https://github.com/eslint/eslint/pull/10109 already attempts to handle it

[fvictorio]

Do you folks think this could be a good first contribution? I’d like to give it a try.