chore: move multi-model into single sub module (#1443)

.changeset/cool-cows-lick.md

packages/env/multi-model/package.json

packages/env/package.json

packages/env/src/index.browser.ts

packages/env/src/index.edge-light.ts

packages/env/src/index.ts

packages/env/src/index.workerd.ts

packages/env/src/internal/multi-model/browser.ts

packages/env/src/internal/multi-model/node.ts

packages/env/src/internal/multi-model/non-node.ts

packages/env/src/internal/multi-model/shared.ts

packages/env/src/multi-model.browser.ts

packages/env/src/multi-model.edge-light.ts

packages/env/src/multi-model.ts

packages/env/src/multi-model.workerd.ts

packages/llamaindex/e2e/node/embedding/clip.e2e.ts

packages/providers/clip/src/embedding.ts

packages/providers/huggingface/src/embedding.ts

packages/providers/huggingface/src/llm.ts