[Bug] Top sites do not use full width in landscape mode

[ecsmyth]

Steps to reproduce

1. Add top sites until there are two+ rows in portrait mode
2. Rotate the phone to landscape mode

Expected behavior

Full width of the screen is used to show as many top sites as fit before creating additional rows.

Actual behavior

Device information

• Android device: Samsung Galaxy S10 Int'l
• Fenix version: Fenix Nightly 200226 build 20571807

┆Issue is synchronized with this Jira Task

[gabrielluong]

This seems to be a regression from #8719.

[gabrielluong]

Hi @topotropic, I am wondering what we should expect when we're in landscape mode for Top Sites. Above you can see the changes that was done to force it not expand and match the parent width.

I have included screenshots from #8719 of the previous behaviour:

[topotropic]

@gabrielluong can we keep the margins and fill up the row until it's full and the break to the next row?

[mcarare]

@gabrielluong It is not a regression from #8719, it is just the fact that GridLayoutManager is hardcoded to show 5 elements per row ( const val NUM_COLUMNS = 5 in TopSiteViewHolder )

[LaurentiuApahideanSV]

Verified as fixed on Firefox Preview Nightly 200310 (Build #20700607) GV: 75.0a1-20200309091841 using a Motorala G7 (Android 9) and OnePlus 6T (Android 9). When the device is in landscape mode the Top Sites are no longer limited to 5 per row but rather the length available on the screen and there is no large spacing between top sites.