fix: remove testutils from workspace dep to fix wasm32 CI build

testutils feature pulls in rand/serde_json which are incompatible with
wasm32-unknown-unknown target. Each crate already enables it in
[dev-dependencies] where it belongs.

Author: Kingsman-99

Cargo.toml

@@ -3,7 +3,7 @@ members = ["contracts/split", "contracts/dashboard"]
 resolver = "2"
 
 [workspace.dependencies]
-soroban-sdk = { version = "22.0.0", features = ["testutils"] }
+soroban-sdk = { version = "22.0.0" }
 
 [profile.release]
 opt-level = "z"