[Performance] Remove eager Moment and lodash imports - #10051

Summary

• preserves the existing isMoment and isDate behavior without importing Moment at runtime
• replaces lodash equality and ID helpers in the visualization color store with small local implementations
• adds coverage for date predicate compatibility and unchanged visualization colors

Benchmark

Measured in the representative Agora MCP app:

• removing eager Moment: about 20 KB gzip saved
• simplifying the visualization color store: about 33 KB gzip saved
• final optimized MCP profile: 276 KB gzip, down from 455 KB for published EUI with the full icon registry

Full benchmark, methodology, and trade-offs: https://github.com/elastic/agora/pull/1

The icon allowlist and MCP build settings measured there are separate from this PR.

Validation

• yarn workspace @elastic/eui-theme-common test-unit src/services/vis_color_store.test.ts
• yarn workspace @elastic/eui test-unit services/predicate/common_predicates.test.ts
• TypeScript checks for both packages
• theme-common ESLint
• full EUI workspace and package builds
• Agora payload/runtime benchmark rerun against this exact branch