fix(swift): test template in case of response

Author: Fluf22

templates/swift/tests/client/method.mustache

@@ -1,4 +1,5 @@
-{{#hasResponse}}let response{{#isGeneric}}: Response<{{{returnType}}}<Hit>>{{/isGeneric}} = {{/hasResponse}}{{> tests/method}}
+{{#hasResponse}}let response{{#isGeneric}}: Response<{{{returnType}}}<Hit>>{{/isGeneric}} = {{> tests/method}}{{/hasResponse}}
+{{^hasResponse}}let _{{#isGeneric}}: Response<{{{returnType}}}<Hit>>{{/isGeneric}} = {{> tests/method}}{{/hasResponse}}
 {{^isHelper}}
 {{^isBenchmark}}
 let responseBodyData = try XCTUnwrap(response.bodyData)