change @atproto/xrpc version to void some weird type mismatch nonsense

Author: EmilyxFox

deno.json

@@ -5,7 +5,7 @@
   },
   "imports": {
     "@atproto/api": "npm:@atproto/api@^0.13.18",
-    "@atproto/xrpc": "npm:@atproto/xrpc@^0.7.7",
+    "@atproto/xrpc": "npm:@atproto/xrpc@^0.6.4",
     "@db/sqlite": "jsr:@db/sqlite@^0.12.0",
     "@std/assert": "jsr:@std/assert@1",
     "@std/path": "jsr:@std/path@^1.0.8",