Grid alignment buttons (#6413)

**Problem:**

The alignment buttons at the top of the inspector could be repurposed to
also be useful when dealing with self align/justify for grids and flex.

**Fix:**

This PR does a bunch of things:

1. Rename the `T` and `L` labels in the frame positioning to `X` and `Y`
2. Move the alignment buttons from the top of the editor to above the
`X` and `Y` controls, splitting them into two chain controls
3. Make those buttons control the positioning for flow elements, as well
as controlling justify self/align self for flex or grid children
4. Make those buttons display the current state of the property they're
controlling
5. Make those buttons unset the property if they are clicked again while
active
6. Add a context menu to the right of the buttons to unset the values
(the entry will only show if there _are_ set values) as well as
distribute horizontally/vertically
7. Adjust the radix dropdown menu items so that they are less opaque
when disabled



https://github.com/user-attachments/assets/e749df9a-a94c-4844-ad0e-cbfecf81d08e

## 👀 For the kind reviewers 👀
The actual meat of this PR is in
`editor/src/components/editor/actions/actions.tsx` and
`editor/src/components/inspector/alignment-buttons.tsx`.

Fixes #6412

editor/src/components/canvas/__snapshots__/ui-jsx-canvas-bugs.spec.tsx.snap

@@ -160,6 +160,7 @@ Object {
     "specialSizeMeasurements": Object {
       "alignContent": null,
       "alignItems": null,
+      "alignSelf": null,
       "borderRadius": null,
       "clientHeight": 0,
       "clientWidth": 0,
@@ -219,6 +220,7 @@ Object {
       },
       "immediateParentProvidesLayout": true,
       "justifyContent": null,
+      "justifySelf": null,
       "layoutSystemForChildren": null,
       "margin": Object {},
       "naturalHeight": null,
@@ -307,6 +309,7 @@ Object {
     "specialSizeMeasurements": Object {
       "alignContent": null,
       "alignItems": null,
+      "alignSelf": null,
       "borderRadius": null,
       "clientHeight": 0,
       "clientWidth": 0,
@@ -366,6 +369,7 @@ Object {
       },
       "immediateParentProvidesLayout": true,
       "justifyContent": null,
+      "justifySelf": null,
       "layoutSystemForChildren": null,
       "margin": Object {},
       "naturalHeight": null,