[Compound] Implement Snackbars based on designs (#1054)

* Make `InternalButton` internal instead of private so it can be customised.

Also, change the `ButtonColors.contentColor` for text buttons to `LocalContentColor.current` by default.

* Add temporary color for Snackbar action label

* Implement `Snackbar` component based on Compound

* Propagate changes to all other components

* Use right Preview annotation config

* Move `ButtonVisuals` to their own file

* Update screenshots

* Make previews internal

* Update screenshots

* Set a custom token for contentColor in AppBars

* Change 'Label' to 'Action' in the previews

* Add changelog

* Update screenshots

---------

Co-authored-by: ElementBot <benoitm+elementbot@element.io>

features/invitelist/impl/src/main/kotlin/io/element/android/features/invitelist/impl/components/InviteSummaryRow.kt

@@ -135,7 +135,7 @@ internal fun DefaultInviteSummaryRow(
                     text = stringResource(CommonStrings.action_decline),
                     onClick = onDeclineClicked,
                     modifier = Modifier.weight(1f),
-                    buttonSize = ButtonSize.Medium,
+                    size = ButtonSize.Medium,
                 )
 
                 Spacer(modifier = Modifier.width(12.dp))
@@ -144,7 +144,7 @@ internal fun DefaultInviteSummaryRow(
                     text = stringResource(CommonStrings.action_accept),
                     onClick = onAcceptClicked,
                     modifier = Modifier.weight(1f),
-                    buttonSize = ButtonSize.Medium,
+                    size = ButtonSize.Medium,
                 )
             }
         }