no-non-null-asserted-optional-chain
Disallow non-null assertions after an optional chain expression.
?. optional chain expressions provide undefined if an object is null or
undefined. Using a ! non-null assertion to assert the result of an ?.
optional chain expression is non-nullable is likely wrong.
Invalid:
foo?.bar!;
foo?.bar()!;
Valid:
foo?.bar;
foo?.bar();