Avoid PLW0108 for forward references

[Sean-Kenneth-Doherty]

Summary

• Avoid reporting PLW0108 when inlining the lambda would evaluate a referenced callable earlier than the lambda currently does
• Keep reporting and fixing cases where the callable binding is already available at the replacement location
• Add fixture and snapshot coverage for module-level and local forward-reference cases

Validation

• cargo test -p ruff_linter unnecessary_lambda
• cargo check -p ruff_linter
• cargo fmt --check -- crates/ruff_linter/src/rules/pylint/rules/unnecessary_lambda.rs
• git diff --check upstream/main...HEAD

[Sean-Kenneth-Doherty]

Local validation for fd2a5a27accb36cf9de2cfb0bb27cbc8db6e6a48:

• cargo test -p ruff_linter unnecessary_lambda passed: the targeted PLW0108 snapshot test passed (1 passed, 2776 filtered out).
• cargo check -p ruff_linter passed.
• cargo fmt --check -- crates/ruff_linter/src/rules/pylint/rules/unnecessary_lambda.rs passed.
• git diff --check upstream/main...HEAD and git diff --check passed.
• uvx prek run --from-ref upstream/main passed (merge conflicts, typos, and rustfmt; unrelated hooks skipped because no matching files changed).

The local checkout is clean after validation.