Remove DesignKit package (#1886)

- Move button styles to Compound
- Rename text style to AuthenticationTextStyle as its only in the auth flow.
- Add the brand colour locally for now until its included in Compound.

* Update snapshots.

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Co-authored-by: Stefan Ceriu <stefan.ceriu@gmail.com>

ElementX/Sources/Screens/InvitesScreen/View/InvitesScreenCell.swift

@@ -105,11 +105,11 @@ struct InvitesScreenCell: View {
     private var buttons: some View {
         HStack(spacing: 12) {
             Button(L10n.actionDecline, action: declineAction)
-                .buttonStyle(.elementCapsule)
+                .buttonStyle(.compound(.secondary, size: .medium))
                 .accessibilityIdentifier(A11yIdentifiers.invitesScreen.decline)
             
             Button(L10n.actionAccept, action: acceptAction)
-                .buttonStyle(.elementCapsuleProminent)
+                .buttonStyle(.compound(.primary, size: .medium))
                 .accessibilityIdentifier(A11yIdentifiers.invitesScreen.accept)
         }
     }