Update to Angular 18 (#2508)

# Pull Request

## 🤨 Rationale

Part of Angular 18 migration ([AzDO work
item](https://dev.azure.com/ni/DevCentral/_workitems/edit/2973920))

## 👩‍💻 Implementation

- bumped Angular dependency versions from 17 to 18
- updated Angular projects to use new, Angular-18-compatible
`ni-eslint-config-angular` version
- updated forked Angular files in
`angular-workspace/nimble-angular/src/thirdparty`
- No meaningful changes were made. In some cases I left the original
imports but commented them out, rather than removing them like we had
done before.
- auto-fix some new, minor lint violations:
   - unnecessary uses of non-null assertion (`!`)
   - unnecessary uses of `as const` on string literals
- one prefer-optional-chaining fix (e.g. `!x.foo?.bar()` instead of
`!x.foo || !x.foo.bar()`)
   - one forbidden use of `Readonly<Foo[]>` (change to `readonly Foo[]`)

## 🧪 Testing

Builds and automated tests pass

## ✅ Checklist

- [x] I have updated the project documentation to reflect my changes or
determined no changes are needed.

---------

Co-authored-by: rajsite <[email protected]>

change/@ni-nimble-angular-b3775054-4fc0-4ca5-abdf-18a89277520c.json

@@ -0,0 +1,7 @@
+{
+  "type": "major",
+  "comment": "Update to Angular 18",
+  "packageName": "@ni/nimble-angular",
+  "email": "[email protected]",
+  "dependentChangeType": "patch"
+}

change/@ni-nimble-components-1de4f0a4-b17e-4364-9c78-5ba1fbeecd6f.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "Minor lint fixes",
+  "packageName": "@ni/nimble-components",
+  "email": "[email protected]",
+  "dependentChangeType": "patch"
+}

change/@ni-spright-angular-a14c5d29-35ba-4504-b945-3ccb3b044c1f.json

@@ -0,0 +1,7 @@
+{
+  "type": "major",
+  "comment": "Update to Angular 18",
+  "packageName": "@ni/spright-angular",
+  "email": "[email protected]",
+  "dependentChangeType": "patch"
+}