fix(perf): Chunk and lazy load BackgroundFiltersProvider

[oliverlaz]

💡 Overview

With the introduction of the revamped video filters in #1977, our SDK grew by ~250KB after minification.
While filters are an optional feature, many bundlers were unnecessarily bundling them in the main app chunk, slightly increasing the JS download and parsing time.

With this PR, BackgroundFiltersProvider and the content of the @stream-io/video-filters-web package live in a separate, lazily loaded chunk of our SDK. This trick moves those ~250KB outside of the main bundle, hence restoring the previous performance and size constraints.

Implementation notes

Some code restructuring was necessary, so now we have:

• types.ts - a shared module containing all types, used in both chunks
• BackgroundFiltersProvider.tsx - code splitting happens here
• BackgroundFilters.tsx - the original, slightly slimmed down implementation