[components] Merge https://github.com/mozilla-mobile/android-components/pull/7440 https://github.com/mozilla-mobile/android-components/pull/7481 (part 2)
7440: Closes https://github.com/mozilla-mobile/android-components/issues/7577: Guess download file size when not provided by the website r=csadilek a=Amejia481
7481: Issue https://github.com/mozilla-mobile/android-components/issues/7480: Migrate feature-session to use BrowserStore. r=NotWoods,csadilek a=pocmo
Starting to migrate some classes in `feature-session`.
Co-authored-by: Arturo Mejia <arturomejiamarmol@gmail.com>
Co-authored-by: Sebastian Kaspari <s.kaspari@gmail.com>