fix: make sure to check std is taken from sway-lib-std folder

[kayagokalp]

Description

This PR adds a ad-hoc solution for #5811. Basically checks if the fetched package is 'std' and if so, only package from 'sway-lib-std' folder is accepted for that package.

[kayagokalp]

This one is not easy to test, I applied these changes onto 0.52.0 tag and verified to build a project that was not building before.

[github-actions]

Benchmark for 8a676fd

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Test	Base	PR	%
code_action	5.5±0.32ms	5.5±0.05ms	0.00%
code_lens	293.1±10.64ns	288.8±11.59ns	-1.47%
compile	6.0±0.05s	6.0±0.09s	0.00%
completion	5.0±0.08ms	5.0±0.13ms	0.00%
did_change_with_caching	5.4±0.02s	5.5±0.06s	+1.85%
document_symbol	1014.4±30.90µs	968.5±28.50µs	-4.52%
format	87.9±3.12ms	88.1±0.60ms	+0.23%
goto_definition	362.8±11.22µs	363.6±19.36µs	+0.22%
highlight	9.1±0.32ms	9.1±0.20ms	0.00%
hover	595.5±24.05µs	619.1±23.27µs	+3.96%
idents_at_position	122.2±0.45µs	124.0±1.18µs	+1.47%
inlay_hints	669.0±22.65µs	674.5±16.50µs	+0.82%
on_enter	497.0±17.56ns	508.2±12.02ns	+2.25%
parent_decl_at_position	3.7±0.03ms	3.7±0.04ms	0.00%
prepare_rename	359.9±4.19µs	357.9±9.88µs	-0.56%
rename	9.5±0.04ms	9.6±0.16ms	+1.05%
semantic_tokens	1040.4±20.16µs	1086.6±28.34µs	+4.44%
token_at_position	348.8±2.85µs	360.6±2.61µs	+3.38%
tokens_at_position	3.7±0.02ms	3.7±0.02ms	0.00%
tokens_for_file	412.8±12.05µs	420.3±1.50µs	+1.82%
traverse	43.8±1.92ms	43.7±1.20ms	-0.23%