Fix parser bug for typed dictionaries with custom classes as values

[tracefree]

Fixes #96881

I assume that this was an oversight during a larger refactorization since script_path was defined and initialized but never used. I added what I assume to be its originally intended use and it fixes the the bug for me.

[Repiteo]

Good catch!

[dalexeev]

CC @godotengine/gdscript, @rune-scape

[rune-scape]

i should add a comment to this function, as its actually a very delicate piece of code,
theres a couple things wrong with this change

+it returns early, so the parser ref doesn't get cached
+it doesn't check to make sure the parser has the class, which is the point of the function

it needs to get the correct parser_ref that has the requested class bc after #94871 there can technically be 2 parser_refs floating around and the analyzer needs to find the correct one

get_depended_parser_for is intentionally not called in this function bc the parser its looking for may not be in the gdscript cache but it should be somewhere in the dependancy chain, and this function looks for it

if it cant find it there is probably a bug somewhere else

an alternate fix might be to look in the gdscript cache for it, without using get_depended_parser_for if it cant find it anywhere else

[tracefree]

Thanks for the correction! I'm very new to this part of the codebase so I appreciate the insight. Do you know why the script_path variable was defined but not used (unless I missed something), and do you have a suggestion for where the real cause of the bug could be?