Search for post/page/product title returns inconsistent results for words with accents

Languages like Portuguese use a lot of accents. Search for post/page/product title returns Inconsistent results for words with accents.

This started as a product issue for the Woo app https://github.com/woocommerce/woocommerce-ios/issues/4801 but @koke quickly identified that this only happens on WP.com sites, both simple and Atomic.

Tested:

* On both Calypso and the WP Admin interface for WP.com sites.
* With English and Portuguese set as the interface language in https://wordpress.com/me/account

### Steps to reproduce the behavior

Steps to reproduce the behavior:
1. Add a post, page, or Woo product with at least a word with accents. In my case, _catálogo_
2. Go to the respecitve pages and tap on search
3. Type the words, partially or not.
4. You'll get no results

#### What I expected to happen

To list all results despite the lack of accents.

#### What actually happened

Using _catálogo_, if I search for:

- _cata_: all results
- _catalogo_: no results
- _catal_: no results
- _logo_: all results

### Context
Dogfooding.

#### Does this happen on simple or atomic sites or both?
Both.

#### Is there any console output or error text?
No.

#### Level of impact (Does it block purchases? Does it affect more than just one site?)
Low.

#### Reproducibility (Consistent, Intermittent) Leave empty for consistent.

Reproduce the issue in Calypso and WP Admin on both simple and Atomic WP.com sites using titles containing accents, such as “catálogo,” and compare accented and unaccented partial searches. Trace the search entry point and verify that searches without accents return the same matching post, page, or product results.

Written by the indexing model from the issue text.