Replace deprecated ESLint context methods with v9 compatible alternatives

[Copilot]

This PR updates all ESLint rules to use the new context API methods introduced in ESLint v9, as outlined in the ESLint v9 migration guide.

Changes

All deprecated context methods have been replaced with their modern equivalents:

• context.getSourceCode() → context.sourceCode
• context.getScope() → sourceCode.getScope(node)

Previously, the codebase used fallback patterns for backward compatibility:

// Old approach with fallback
const sourceCode = context.sourceCode || context.getSourceCode();
const scope = sourceCode.getScope ? sourceCode.getScope(node) : context.getScope();

Now uses the direct ESLint v9 API:

// New ESLint v9 compatible approach
const sourceCode = context.sourceCode;
const scope = sourceCode.getScope(node);

Files Updated

Rules (6 files):

• rules/detect-child-process.js
• rules/detect-no-csrf-before-method-override.js
• rules/detect-non-literal-fs-filename.js
• rules/detect-non-literal-regexp.js
• rules/detect-non-literal-require.js
• rules/detect-unsafe-regex.js

Test utilities (2 files):

• test/utils/import-utils.js
• test/utils/is-static-expression.js

Testing

✅ All 221 existing tests pass
✅ All linters pass (ESLint, Markdownlint, eslint-doc-generator)
✅ No deprecated method calls remain in the codebase

This change ensures the plugin is fully compatible with ESLint v9 and removes reliance on deprecated APIs.

Original prompt

We need to update each rule that uses deprecated methods on context to use their replacements. See https://eslint.org/blog/2023/09/preparing-custom-rules-eslint-v9/

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[nzakas]

Looks like we already had handled these methods. opening a new PR for the newly removed methods in v10.