Fix instant transformations not being committed when used in succession

Also:
- Fix holding down keys repeatedly committing instant transformations, and disallow starting instant during non-instant
- Fix echoed inputs starting new instant transformations after clicking to confirm, and disallow left mouse release committing instant transformations

editor/plugins/node_3d_editor_plugin.cpp

@@ -1975,7 +1975,7 @@ void Node3DEditorViewport::_sinput(const Ref<InputEvent> &p_event) {
 						}
 					}
 
-					if (_edit.mode != TRANSFORM_NONE) {
+					if (!_edit.instant && _edit.mode != TRANSFORM_NONE) {
 						Node3D *selected = spatial_editor->get_single_selected_node();
 						Node3DEditorSelectedItem *se = selected ? editor_selection->get_node_editor_data<Node3DEditorSelectedItem>(selected) : nullptr;
 
@@ -2399,15 +2399,30 @@ void Node3DEditorViewport::_sinput(const Ref<InputEvent> &p_event) {
 		if (ED_IS_SHORTCUT("spatial_editor/cancel_transform", p_event) && _edit.mode != TRANSFORM_NONE) {
 			cancel_transform();
 		}
-		if (!is_freelook_active()) {
-			if (ED_IS_SHORTCUT("spatial_editor/instant_translate", p_event)) {
-				begin_transform(TRANSFORM_TRANSLATE, true);
+		if (!is_freelook_active() && !k->is_echo()) {
+			if (ED_IS_SHORTCUT("spatial_editor/instant_translate", p_event) && _edit.mode != TRANSFORM_TRANSLATE) {
+				if (_edit.mode == TRANSFORM_NONE) {
+					begin_transform(TRANSFORM_TRANSLATE, true);
+				} else if (_edit.instant) {
+					commit_transform();
+					begin_transform(TRANSFORM_TRANSLATE, true);
+				}
 			}
-			if (ED_IS_SHORTCUT("spatial_editor/instant_rotate", p_event)) {
-				begin_transform(TRANSFORM_ROTATE, true);
+			if (ED_IS_SHORTCUT("spatial_editor/instant_rotate", p_event) && _edit.mode != TRANSFORM_ROTATE) {
+				if (_edit.mode == TRANSFORM_NONE) {
+					begin_transform(TRANSFORM_ROTATE, true);
+				} else if (_edit.instant) {
+					commit_transform();
+					begin_transform(TRANSFORM_ROTATE, true);
+				}
 			}
-			if (ED_IS_SHORTCUT("spatial_editor/instant_scale", p_event)) {
-				begin_transform(TRANSFORM_SCALE, true);
+			if (ED_IS_SHORTCUT("spatial_editor/instant_scale", p_event) && _edit.mode != TRANSFORM_SCALE) {
+				if (_edit.mode == TRANSFORM_NONE) {
+					begin_transform(TRANSFORM_SCALE, true);
+				} else if (_edit.instant) {
+					commit_transform();
+					begin_transform(TRANSFORM_SCALE, true);
+				}
 			}
 		}