nix: Update flake, remove legacy Darwin SDK usage (#37254)

`darwin.apple_sdk.frameworks` has been obsoleted and is no longer
required to be specified explicitly as per [Nixpkgs Reference
Manual](https://nixos.org/manual/nixpkgs/stable/#sec-darwin-legacy-frameworks).

@P1n3appl3 not sure what the process for updating Nix is, so lemme know
if this is desired/acceptable!

Release Notes:

- N/A

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "crane": {
       "locked": {
-        "lastModified": 1754269165,
-        "narHash": "sha256-0tcS8FHd4QjbCVoxN9jI+PjHgA4vc/IjkUSp+N3zy0U=",
+        "lastModified": 1755993354,
+        "narHash": "sha256-FCRRAzSaL/+umLIm3RU3O/+fJ2ssaPHseI2SSFL8yZU=",
         "owner": "ipetkov",
         "repo": "crane",
-        "rev": "444e81206df3f7d92780680e45858e31d2f07a08",
+        "rev": "25bd41b24426c7734278c2ff02e53258851db914",
         "type": "github"
       },
       "original": {
@@ -33,10 +33,10 @@
     "nixpkgs": {
       "locked": {
         "lastModified": 315532800,
-        "narHash": "sha256-5VYevX3GccubYeccRGAXvCPA1ktrGmIX1IFC0icX07g=",
-        "rev": "a683adc19ff5228af548c6539dbc3440509bfed3",
+        "narHash": "sha256-E8CyvVDZuIsF7puIw+OLkrFmhj3qUV+iwPcNbBhdcxM=",
+        "rev": "a918bb3594dd243c2f8534b3be01b3cb4ed35fd1",
         "type": "tarball",
-        "url": "https://releases.nixos.org/nixpkgs/nixpkgs-25.11pre840248.a683adc19ff5/nixexprs.tar.xz"
+        "url": "https://releases.nixos.org/nixpkgs/nixpkgs-25.11pre854010.a918bb3594dd/nixexprs.tar.xz"
       },
       "original": {
         "type": "tarball",
@@ -58,11 +58,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1754575663,
-        "narHash": "sha256-afOx8AG0KYtw7mlt6s6ahBBy7eEHZwws3iCRoiuRQS4=",
+        "lastModified": 1756607787,
+        "narHash": "sha256-ciwAdgtlAN1PCaidWK6RuWsTBL8DVuyDCGM+X3ein5Q=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "6db0fb0e9cec2e9729dc52bf4898e6c135bb8a0f",
+        "rev": "f46d294b87ebb9f7124f1ce13aa2a5f5acc0f3eb",
         "type": "github"
       },
       "original": {

nix/build.nix

@@ -145,7 +145,6 @@ let
         ]
         ++ lib.optionals stdenv'.hostPlatform.isDarwin [
           apple-sdk_15
-          darwin.apple_sdk.frameworks.System
           (darwinMinVersionHook "10.15")
         ];