accounts/abi/bind: correctly handle structs used only as constructor params (#23940)

The `structs` map is populated by iterating over all methods except the constructor, which results in a nil-pointer dereference.

I've first reproduced the problem with a new test and then implemented the fix.

Co-authored-by: Arran Schlosberg <me@arranschlosberg.com>

accounts/abi/bind/bind.go

@@ -88,6 +88,13 @@ func Bind(types []string, abis []string, bytecodes []string, fsigs []map[string]
 			transactIdentifiers = make(map[string]bool)
 			eventIdentifiers    = make(map[string]bool)
 		)
+
+		for _, input := range evmABI.Constructor.Inputs {
+			if hasStruct(input.Type) {
+				bindStructType[lang](input.Type, structs)
+			}
+		}
+
 		for _, original := range evmABI.Methods {
 			// Normalize the method for capital cases and non-anonymous inputs/outputs
 			normalized := original