bug: Searchbar backbutton does not respect config setting

[masimplo]

Bug Report

Ionic version:

[x] 4.x

Current behavior:

Changing the back-button icon to a different icon than the default arrow-back, makes the searchbar back icon inconsistent in design with the rest of the app, since it uses a hard coded value of md-arrow-back.
You can set the button in each searchbar explicitly as a workaround, but I think it makes sense for the searchbar back to follow the rest of the app design (I might be wrong)

Expected behavior:

The searchbar component back icon (Android only) should be the same as the custom back icon.

Steps to reproduce:

Add a custom back icon through the config.
Add a searchbar component.
The icon hasn't changed.

[UTSOURCE]

I also have the same problem.

[ionitron-bot]

Thanks for the issue! This issue is being locked to prevent comments that are not relevant to the original issue. If this is still an issue with the latest version of Ionic, please create a new issue and ensure the template is fully filled out.