[DOCS] : swap allocation sections

[georgewallace]

Swapping the order based on https://github.com/elastic/search-team/issues/8634

[github-actions]

Documentation preview:

• ✨ Changed pages

[elasticsearchmachine]

Pinging @elastic/es-docs (Team:Docs)

[linyaru]

• I think we should modify the header of the first example section to be "ELSER service example"

• "The following example shows how to create an inference endpoint called my-elser-model to perform a sparse_embedding task type and configure adaptive allocations." could become "The following example shows how to create an inference endpoint called my-elser-model to perform a sparse_embedding task type and configure adaptive allocations (recommended)."
• The next section header could be "Creating ELSER service without adaptive allocations"

• "The following example shows how to create an inference endpoint called my-elser-model to perform a sparse_embedding task type." could become "The following example shows how to create an inference endpoint called my-elser-model to perform a sparse_embedding task type when adaptive allocations isn't required or trained model autoscaling isn't available."

[georgewallace]

@linyaru made the changes as you suggested. Please take another look and let me know.

[linyaru]

Sorry for missing this, LGTM!

[elasticsearchmachine]

💚 Backport successful

Status	Branch	Result
✅	8.16
✅	8.17
✅	8.x