fix[lang]!: getter types for interfaces

[charles-cooper]

What I did

for interface compatibility reasons, apparently InterfaceT reported that its getter signature was AddressT(). this changes the getter signature to the "more correct" InterfaceT. it also relaxes type checking for interfaces, allowing interfaces to be assigned to address in the type system.

fix #3954 (comment)
fix #3701 (comment)

How I did it

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[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 58.82%. Comparing base (7d28a50) to head (c3eef76).
Report is 2 commits behind head on master.

❗ Current head c3eef76 differs from pull request most recent head 342f950. Consider uploading reports for the commit 342f950 to get more accurate results

Files	Patch %	Lines
vyper/semantics/types/module.py	0.00%	1 Missing ⚠️

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Additional details and impacted files

@@             Coverage Diff             @@
##           master    #3961       +/-   ##
===========================================
- Coverage   90.81%   58.82%   -31.99%     
===========================================
  Files          98       95        -3     
  Lines       14867    14454      -413     
  Branches     3309     3205      -104     
===========================================
- Hits        13501     8503     -4998     
- Misses        945     5320     +4375     
- Partials      421      631      +210     

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