feat: show a mid point for linear elements (#5534)

* feat: Add a mid point for linear elements

* fix tests

* show mid point only on hover

* hacky fix :(

* don't add mid points if present and only add outside editor

* improve styling and always show phantom point instead of just on hover

* fix tests

* fix

* only add polyfill for test

* add hover state for phantom point

* fix tests

* fix

* Add Array.at polyfill

* reuse `centerPoint()` helper

* reuse `distance2d`

* use `Point` type

Co-authored-by: dwelle <luzar.david@gmail.com>

src/tests/__snapshots__/regressionTests.test.tsx.snap

@@ -10982,6 +10982,7 @@ Object {
     "hoverPointIndex": -1,
     "isDragging": false,
     "lastUncommittedPoint": null,
+    "midPointHovered": false,
     "pointerDownState": Object {
       "lastClickedPoint": -1,
       "prevSelectedPointsIndices": null,
@@ -11207,6 +11208,7 @@ Object {
     "hoverPointIndex": -1,
     "isDragging": false,
     "lastUncommittedPoint": null,
+    "midPointHovered": false,
     "pointerDownState": Object {
       "lastClickedPoint": -1,
       "prevSelectedPointsIndices": null,
@@ -11659,6 +11661,7 @@ Object {
     "hoverPointIndex": -1,
     "isDragging": false,
     "lastUncommittedPoint": null,
+    "midPointHovered": false,
     "pointerDownState": Object {
       "lastClickedPoint": -1,
       "prevSelectedPointsIndices": null,
@@ -12063,6 +12066,7 @@ Object {
     "hoverPointIndex": -1,
     "isDragging": false,
     "lastUncommittedPoint": null,
+    "midPointHovered": false,
     "pointerDownState": Object {
       "lastClickedPoint": -1,
       "prevSelectedPointsIndices": null,