Move Str methods that other Str methods call to module-level functions

[collectioneur]

react-native-worklets 0.13 removed Worklet Context Objects (software-mansion/react-native-reanimated#10411). In App without Bundle Mode (our default Re.Pack builds), this inside Str methods no longer points to Str on the LiveMarkdownRuntime. As a result, typing a link in the composer crashes in Str.sanitizeURL → this.cutBefore.

This PR moves the Str methods that other Str methods call to module-level functions in lib/str.ts and calls them directly instead of through this:

compare, caseInsensitiveCompare, contains, cutAfter, cutBefore, extractEmailDomain, getExtension, getRawByteSize, htmlDecode, htmlEncode, isTypeOf, isNumber, isString, isUndefined, isValidE164Phone, isValidEmail, maskFirstNCharacters, removeSMSDomain, removeTrailingComma, startsWith

Every one of them is still exposed on Str under the same name with the same JSDoc, so the public Str API and behavior are unchanged. There are no this. references left in lib/str.ts.

This is the upstream version of the expensify-common patch added in Expensify/App#102266 (the reanimated 4.7.0 / worklets 0.13.0 upgrade). Once this is released and App bumps expensify-common, that patch can be removed.

Fixed Issues

$ Expensify/App#101440

Tests

1. Existing unit tests cover the change: __tests__/Str-test.js covers the Str methods, and the ExpensiMark tests exercise Str indirectly.
2. Ran npx tsc --noEmit, npx eslint lib/str.ts, npm run build and npx jest: no type or lint errors, and all 569 tests pass.

QA

1. Tested in App through Bump react-native-reanimated to 4.7.0 and react-native-worklets to 0.13.0 App#102266, where the same change is applied as a patch. On iOS and Android, open a chat and type *bold* _italic_ ~strike~ `code` @here https://expensify.com. Verify the formatting is applied live and that typing the link does not crash. Repeat on web.

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[collectioneur]

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[mountiny]

LGTM, I will move this ahead as we need this to be merged before continuing with prs required for expo and react native upgrades