Update path and extensions.ui

Author: devisscher

discounts/rust/discount/default/shopify.extension.toml.liquid

@@ -19,8 +19,5 @@ description = "t:description"
 
   [extensions.build]
   command = "cargo build --target=wasm32-wasip1 --release"
-  path = "{{handle | replace: " ", "-" | downcase}}.wasm"
+  path = "target/wasm32-wasip1/release/{{handle | replace: " ", "-" | downcase}}.wasm"
   watch = [ "src/**/*.rs" ]
-
-  [extensions.ui]
-  handle = "{{handle}}"