chore: nix shell to support playwright e2e tests (#12917)

* chore: nix shell to support playwright e2e tests

nix is running an older version of chromium, so had to reduce the
playwright version.

* Add to e2e readme

* add enterprise test comment

* add note about install to readme

* make fmt

* remove shellhook message

Co-authored-by: Kayla Washburn-Love <mckayla@hey.com>

* add link to nixos playwright package to get version

* formatting

---------

Co-authored-by: Kayla Washburn-Love <mckayla@hey.com>

flake.lock

@@ -43,11 +43,11 @@
         "systems": "systems_2"
       },
       "locked": {
-        "lastModified": 1705309234,
-        "narHash": "sha256-uNRRNRKmJyCRC/8y1RqBkqWBLM034y4qN7EprSdmgyA=",
+        "lastModified": 1710146030,
+        "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "1ef2e671c3b0c19053962c07dbda38332dcebf26",
+        "rev": "b1d9ab70662946ef0850d488da1c9019f3a9752a",
         "type": "github"
       },
       "original": {
@@ -73,11 +73,11 @@
     },
     "nixpkgs_2": {
       "locked": {
-        "lastModified": 1706550542,
-        "narHash": "sha256-UcsnCG6wx++23yeER4Hg18CXWbgNpqNXcHIo5/1Y+hc=",
+        "lastModified": 1712439257,
+        "narHash": "sha256-aSpiNepFOMk9932HOax0XwNxbA38GOUVOiXfUVPOrck=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "97b17f32362e475016f942bbdfda4a4a72a8a652",
+        "rev": "ff0dbd94265ac470dda06a657d5fe49de93b4599",
         "type": "github"
       },
       "original": {