feat: Get number of parameters of a layer and a nn

[TellemHD]

Closes #855

Summary of Changes

• feat: Get number of parameters of a layer and a nn
• adds UnitTests

Erst accepten und mergen, wenn #908 fertig ist!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[github-actions]

🦙 MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ PYTHON	black	20	0	0	1.66s
✅ PYTHON	mypy	20		0	2.97s
✅ PYTHON	ruff	20	0	0	0.4s
✅ REPOSITORY	git_diff	yes		no	0.39s

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[codecov]

Codecov Report

Attention: Patch coverage is 88.57143% with 8 lines in your changes missing coverage. Please review.

Project coverage is 97.66%. Comparing base (6f63a6c) to head (c77d58d).
Report is 10 commits behind head on main.

Files	Patch %	Lines
src/safeds/ml/nn/typing/_tensor_shape.py	55.55%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #910      +/-   ##
==========================================
- Coverage   97.67%   97.66%   -0.02%     
==========================================
  Files         120      123       +3     
  Lines        6234     6626     +392     
==========================================
+ Hits         6089     6471     +382     
- Misses        145      155      +10     

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