Fix temporary value not released when used as a dictionary key

modules/gdscript/gdscript_compiler.cpp

@@ -966,6 +966,9 @@ GDScriptCodeGenerator::Address GDScriptCompiler::_parse_expression(CodeGen &code
 				} else {
 					gen->write_set(prev_base, key, assigned);
 				}
+				if (key.mode == GDScriptCodeGenerator::Address::TEMPORARY) {
+					gen->pop_temporary();
+				}
 				if (assigned.mode == GDScriptCodeGenerator::Address::TEMPORARY) {
 					gen->pop_temporary();
 				}