feat: Enter and Exit line editor via context menu (#5719)

* feat: Enter and exit line editor via context menu

* Add tests

* fix

* review fixes

* fix

src/actions/actionLinearEditor.ts

@@ -0,0 +1,49 @@
+import { getNonDeletedElements } from "../element";
+import { LinearElementEditor } from "../element/linearElementEditor";
+import { isLinearElement } from "../element/typeChecks";
+import { ExcalidrawLinearElement } from "../element/types";
+import { getSelectedElements } from "../scene";
+import { register } from "./register";
+
+export const actionToggleLinearEditor = register({
+  name: "toggleLinearEditor",
+  trackEvent: {
+    category: "element",
+  },
+  contextItemPredicate: (elements, appState) => {
+    const selectedElements = getSelectedElements(elements, appState);
+    if (selectedElements.length === 1 && isLinearElement(selectedElements[0])) {
+      return true;
+    }
+    return false;
+  },
+  perform(elements, appState, _, app) {
+    const selectedElement = getSelectedElements(
+      getNonDeletedElements(elements),
+      appState,
+      true,
+    )[0] as ExcalidrawLinearElement;
+
+    const editingLinearElement =
+      appState.editingLinearElement?.elementId === selectedElement.id
+        ? null
+        : new LinearElementEditor(selectedElement, app.scene);
+    return {
+      appState: {
+        ...appState,
+        editingLinearElement,
+      },
+      commitToHistory: false,
+    };
+  },
+  contextItemLabel: (elements, appState) => {
+    const selectedElement = getSelectedElements(
+      getNonDeletedElements(elements),
+      appState,
+      true,
+    )[0] as ExcalidrawLinearElement;
+    return appState.editingLinearElement?.elementId === selectedElement.id
+      ? "labels.lineEditor.exit"
+      : "labels.lineEditor.edit";
+  },
+});