[Neue] Buttons (#5406)

* Re-align button sizing

(cherry picked from commit bcec243bb59dfe468313d98ba61f464d9750feec)

* Use large, small, tiny

(cherry picked from commit 1dc333c2993ab7f2e0ac750c0670dcec9a7069d0)

* Tweaks

src/view/com/notifications/FeedItem.tsx

@@ -412,7 +412,7 @@ function SayHelloBtn({profile}: {profile: AppBskyActorDefs.ProfileViewBasic}) {
       label={_(msg`Say hello!`)}
       variant="ghost"
       color="primary"
-      size="xsmall"
+      size="small"
       style={[a.self_center, {marginLeft: 'auto'}]}
       disabled={isLoading}
       onPress={async () => {