remove unused ref-cast dep

Author: rklaehn

Cargo.lock

@@ -58,7 +58,6 @@ quinn = { package = "iroh-quinn", version = "0.12", features = ["ring"] }
 rand = "0.8"
 range-collections = "0.4.0"
 redb = { version = "2.2.0", optional = true }
-ref-cast = { version = "1.0.23", optional = true }
 reflink-copy = { version = "0.1.8", optional = true }
 self_cell = "1.0.1"
 serde = { version = "1", features = ["derive"] }
@@ -107,7 +106,6 @@ rpc = [
     "dep:nested_enum_utils",
     "dep:strum",
     "dep:futures-util",
-    "dep:ref-cast",
     "dep:portable-atomic",
     "dep:walkdir",
     "downloader",