chore(linting): combobox, silence warnings

[L2D2Grafana]

Summary 📝

• Resolves ESLint / TypeScript noise across the app: migrates several Select usages to @grafana/ui Combobox, tightens types and test typings, and applies small fixes in Mousetrap, KeybindingSet, combineResponses, shardQuerySplitting, and text.ts (including replacing an invalid deprecation disable with @typescript-eslint/no-deprecated for the execCommand fallback).
• Replaces the “Add label” popover implementation with a searchable Input + scrollable role="listbox" list so saved/default labels can show a Grafana save icon beside the name; placeholder and tooltip behavior stay aligned with existing copy (“Search labels”).
• Minor config/test harness updates (eslint.config.mjs, jest-setup.js) and a locale string touch-up where needed.

Test 🧪

• yarn typecheck
• yarn lint
• Check select udpate to combobox manually