Enhance the security warning system by allowing the configuration of the security URL for external API deployments, utilizing the existing `legalUrls.security` config field.
### Description The security warning system currently uses a hardcoded URL (`https://jitsi.org/security/`) which limits external API deployments. However, the config structure already includes `legalUrls.security` field that should be utilized. ### Solution Leverage existing `legalUrls.security` config field by: 1. Adding `DEFAULT_SECURITY_URL` constant 2. Enhancing [getLegalUrls()](cci:1://file:///c:/Users/hp/Documents/Work/git%20forked/jitsi-meet/react/features/base/config/functions.any.ts:428:0-448:1) to include security URL 3. Creating [getSecurityUrl()](cci:1://file:///c:/Users/hp/Documents/Work/git%20forked/jitsi-meet/react/features/base/util/contants.ts:5:0-16:2) helper that uses existing structure 4. Updating cross-platform implementations ### Benefits - ✅ Uses existing config patterns - ✅ Maintains architectural consistency - ✅ Enables custom security endpoints - ✅ Cross-platform compatibility - ✅ Zero breaking changes ### What solution would you like to see? _No response