build: add tsickle as explicit dependency (#18116)

Adds tsickle as explicit dependency. This is necessary
because we access it from `node_modules/tsickle` in a
Bazel target that wraps tsc with tsickle.

In the past we just relied on the transitive dependency
of `@angular/bazel` being hoisted, but the hoisting is
not guaranteed if the lock file changes (e.g. when running `yarn
upgrade`). In general, dependencies we explicitly access, should be
added as explicit dependencies.

Author: devversion

package.json

@@ -146,6 +146,7 @@
     "terser": "^4.3.9",
     "ts-api-guardian": "^0.4.6",
     "ts-node": "^3.0.4",
+    "tsickle": "^0.37.1",
     "tslint": "^5.20.0",
     "tsutils": "^3.0.0",
     "typescript": "^3.6.4",