[DREAM-713] Bump @rollup/plugin-typescript to v12

Bumps @rollup/plugin-typescript ^8.3.3 -> ^12.3.0 so the rollup build
stops emitting the TS5107 node10 deprecation warning under TypeScript
6.0.

v12 validates that declarationDir sits alongside the bundle output.
Declarations are already produced by the separate `tsc` step in
script/build-assets, so declaration emit is disabled in rollup.config.js
to satisfy the check and avoid redundant work.

Ref: https://community.openproject.org/wp/DREAM-713

Author: myabc

package-lock.json

@@ -72,7 +72,7 @@
     "@primer/primitives": "^11.9.0",
     "@primer/stylelint-config": "^13.6.0",
     "@rollup/plugin-node-resolve": "^16.0.1",
-    "@rollup/plugin-typescript": "^8.3.3",
+    "@rollup/plugin-typescript": "^12.3.0",
     "axe-core": "^4.7.1",
     "chokidar-cli": "^3.0.0",
     "cssnano": "^7.0.1",

package.json

@@ -12,7 +12,10 @@ export default {
   },
   plugins: [
     resolve(),
-    typescript(),
+    // Declarations are emitted by the separate `tsc` step (see script/build-assets),
+    // so disable them here. Avoids @rollup/plugin-typescript v12 requiring
+    // declarationDir to sit alongside the bundle output.
+    typescript({declaration: false, declarationDir: undefined}),
     terser({keep_classnames: /Element$/}) // comment out terser in dev if you want debugger statements
   ],
   onwarn: (warning, warn) => {