security(frontend): pin brace-expansion to 5.0.12+
Raise the brace-expansion override from ^5.0.9 to ^5.0.12. Earlier
versions can run out of stack on deeply nested brace groups and take
quadratic time on the {a},b} rewrite. brace-expansion is a dev-only
transitive dependency of eslint (through minimatch) and only expands
the fixed globs in eslint.config.js.