Revert "[1.x] Upgrade immer from 8.0.1 to 9.0.6 (opensearch-project…

…#786)" (opensearch-project#814)

This reverts commit ff23cc0.

This introduces breaking changes; it will need to wait for 2.0.

Signed-off-by: Tommy Markley <markleyt@amazon.com>

package.json

@@ -394,7 +394,7 @@
     "gulp-sourcemaps": "2.6.5",
     "has-ansi": "^3.0.0",
     "history": "^4.9.0",
-    "immer": "^9.0.6",
+    "immer": "^8.0.1",
     "intl-messageformat-parser": "^1.4.0",
     "jest": "^26.4.2",
     "jest-canvas-mock": "^2.2.0",