Should there be a specialized HashMap<>?

[kidmosey]

When working on the fix for #61808, I resolved it to the fact that one of the overloads for HashMap<>.operator[] inserts a default value instead of throwing an error like the other overload.

Assuming this is by design, would it be a good idea to have a specialization to HashMap<> that disables the insert functionality? Then in cases like the animation node states, where adding a default value isn't desired behavior, we would be able to catch potential issues ahead of time if anyone forgets to do a HashMap<>.has() before each lookup.