Revert "chore: Bump Rust to 1.89 (#35788)" (#35843)

This reverts commit efba2cbfd3.

Unfortunately, the Docker image for 1.89 has not shown up yet. Once it
has, we should re-land this.

Release Notes:

- N/A

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "crane": {
       "locked": {
-        "lastModified": 1754269165,
-        "narHash": "sha256-0tcS8FHd4QjbCVoxN9jI+PjHgA4vc/IjkUSp+N3zy0U=",
+        "lastModified": 1750266157,
+        "narHash": "sha256-tL42YoNg9y30u7zAqtoGDNdTyXTi8EALDeCB13FtbQA=",
         "owner": "ipetkov",
         "repo": "crane",
-        "rev": "444e81206df3f7d92780680e45858e31d2f07a08",
+        "rev": "e37c943371b73ed87faf33f7583860f81f1d5a48",
         "type": "github"
       },
       "original": {
@@ -33,10 +33,10 @@
     "nixpkgs": {
       "locked": {
         "lastModified": 315532800,
-        "narHash": "sha256-5VYevX3GccubYeccRGAXvCPA1ktrGmIX1IFC0icX07g=",
-        "rev": "a683adc19ff5228af548c6539dbc3440509bfed3",
+        "narHash": "sha256-j+zO+IHQ7VwEam0pjPExdbLT2rVioyVS3iq4bLO3GEc=",
+        "rev": "61c0f513911459945e2cb8bf333dc849f1b976ff",
         "type": "tarball",
-        "url": "https://releases.nixos.org/nixpkgs/nixpkgs-25.11pre840248.a683adc19ff5/nixexprs.tar.xz"
+        "url": "https://releases.nixos.org/nixpkgs/nixpkgs-25.11pre821324.61c0f5139114/nixexprs.tar.xz"
       },
       "original": {
         "type": "tarball",
@@ -58,11 +58,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1754575663,
-        "narHash": "sha256-afOx8AG0KYtw7mlt6s6ahBBy7eEHZwws3iCRoiuRQS4=",
+        "lastModified": 1750964660,
+        "narHash": "sha256-YQ6EyFetjH1uy5JhdhRdPe6cuNXlYpMAQePFfZj4W7M=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "6db0fb0e9cec2e9729dc52bf4898e6c135bb8a0f",
+        "rev": "04f0fcfb1a50c63529805a798b4b5c21610ff390",
         "type": "github"
       },
       "original": {