Remove pypi_formula_mappings.json code

[p-linnane]

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We've completed our migration from using pypi_formula_mappings.json to the new pypi_packages DSL (thanks again @botantony for all the great work there!)

This PR removes the log for handling the old JSON file.

[Copilot]

Pull Request Overview

This PR completes the migration from pypi_formula_mappings.json to the new pypi_packages DSL by removing all code related to the old JSON-based system.

Key changes:

• Removed PypiPackages.from_json_file method and associated flags (needs_manual_update, defined_pypi_mapping)
• Eliminated pypi_formula_mappings method and constant from Tap and CoreTap classes
• Simplified formula initialization to use the new DSL exclusively

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
Library/Homebrew/utils/pypi.rb	Removed logic that checked and used JSON-based package mappings
Library/Homebrew/test/tap_spec.rb	Removed test setup and assertions for pypi_formula_mappings
Library/Homebrew/test/spec_helper.rb	Removed cleanup reference to pypi_formula_mappings.json file
Library/Homebrew/test/pypi_packages_spec.rb	Deleted entire test file that tested JSON file parsing
Library/Homebrew/tap_auditor.rb	Removed pypi_formula_mappings from auditor attributes and checks
Library/Homebrew/tap.rb	Removed pypi_formula_mappings method, constant, and cache variable from both Tap and CoreTap classes
Library/Homebrew/pypi_packages.rb	Removed from_json_file factory method and needs_manual_update/defined_pypi_mapping flags
Library/Homebrew/formula.rb	Simplified PypiPackages initialization and removed needs_manual_update parameter from pypi_packages DSL

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[MikeMcQuaid]

Thanks!