chore(deps): Enable legacy-peer-deps, update @blockly/ plugins (#8366)

* chore(deps): Enable npm legacy-peer-deps option

  Add legacy-peer-deps=true to .npmrc:

  - Doesn't install a second, probably out-of-date copy of Blockly
    in node_modules/blockly/.

  - Prevents version conflicts when trying to update @blockly/*
    dev dependencies, beause npm doesn't seem to be clever enough
    to resovle peer dependency version conflicts for the blockly
    package when updating plugins (which have blockly as a peer),
    even if all plugins are updated at the same time.

  - Brings the configuration of the blockly repo in line with
    blockly-samples, for whatever that is worth.  (Might avoid
    problems during monorepo migration.)

* chore(deps): Update @blockly plugins following v11 release

  Achieved by running:

  npm install --save-dev @blockly/theme-modern@latest @blockly/block-test@latest @blockly/dev-tools@latest

* chore(deps): Install missing @typescript-eslint/parser dev dependency

  Our .eslintrc.js references th @typescript-eslint/parser plugin,
  but this plugin was not actually included in the devDependencies
  section in package.json.

package.json

@@ -100,13 +100,14 @@
   },
   "license": "Apache-2.0",
   "devDependencies": {
-    "@blockly/block-test": "^5.0.0",
-    "@blockly/dev-tools": "^7.0.2",
-    "@blockly/theme-modern": "^5.0.0",
+    "@blockly/block-test": "^6.0.4",
+    "@blockly/dev-tools": "^8.0.4",
+    "@blockly/theme-modern": "^6.0.3",
     "@hyperjump/json-schema": "^1.5.0",
     "@microsoft/api-documenter": "^7.22.4",
     "@microsoft/api-extractor": "^7.29.5",
     "@typescript-eslint/eslint-plugin": "^7.3.1",
+    "@typescript-eslint/parser": "^7.16.1",
     "async-done": "^2.0.0",
     "chai": "^5.1.1",
     "concurrently": "^8.0.1",