Hardcode `locationIconRounded` corner size

cornerSize attribute is supposed to be a dimension,
therefore setting it to "50%" makes aapt2 show the following
error message: "styles.xml:225: error: expected dimension
but got (raw string) 50%" when compiling in AOSP environment.

According to Android Studio's design tab, 22dp seems to look
exactly the same as 50% would, as in it adds a light stroke
over the location icon.