Prior to this commit, the `StaticResourceLocation` for favicons would
point to `"/**/favicon.ico"`. This location does not reflect the current
web development landscape, since the png format and size variants are
not supported here. Also, the `"**"` pattern can be costly at runtime
and is deprecated by the new path pattern support in Spring Framework
(see gh-22833).

This commit changes the default locations to `"/favicon.*","/*/icon-*"`,
supporting common use cases such as `"/favicon.ico"`, `"/favicon.png"`
and `"/icons/icon-48x48.png"`.

Closes gh-23126