Add an empty state for the space screen if the user can modify its graph (#6064)

* Add an empty state for the space screen if the user can modify its graph. It adds a new 'create room' button that allows you to open the create room screen with some preset values.

* When computing the editable spaces in `ConfigureRoomPresenter`, also set up the initial selected parent space if possible

* Use `Builder` pattern for `CreateRoomEntryPoint`

* Update screenshots

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Co-authored-by: ElementBot <android@element.io>

features/startchat/impl/src/main/kotlin/io/element/android/features/startchat/impl/StartChatFlowNode.kt

@@ -80,12 +80,14 @@ class StartChatFlowNode(
                         navigator.onRoomCreated(roomId.toRoomIdOrAlias(), emptyList())
                     }
                 }
-                createRoomEntryPoint.createNode(
-                    isSpace = false,
-                    parentNode = this,
-                    buildContext = buildContext,
-                    callback = callback,
-                )
+                createRoomEntryPoint
+                    .builder(
+                        parentNode = this,
+                        buildContext = buildContext,
+                        callback = callback,
+                    )
+                    .setIsSpace(false)
+                    .build()
             }
             NavTarget.JoinByAddress -> {
                 createNode<JoinRoomByAddressNode>(buildContext = buildContext, plugins = listOf(navigator))