test: use coverage instead of equality to test error payload 2

We are going to add missing 'user' payload field for ACCESS_DENIED error
which will break current tests. Let fix tests to allow adding
new payload fields for errors.

This is another place where we test for payload equality.

Need for tarantool/tarantool#9108

config.lua

@@ -248,8 +248,8 @@ if tarantool_version_at_least(2, 4, 1) then
     --   - file: val
     --     line: val
 
-    local function compare_box_error_attributes(expected, actual, attr_provider)
-        for attr, _ in pairs(attr_provider:unpack()) do
+    local function compare_box_error_attributes(expected, actual)
+        for attr, _ in pairs(expected:unpack()) do
             if (attr ~= 'prev') and (attr ~= 'trace') then
                 if expected[attr] ~= actual[attr] then
                     error(('%s expected %s is not equal to actual %s'):format(
@@ -272,8 +272,7 @@ if tarantool_version_at_least(2, 4, 1) then
                    expected.type, expected.message))
         end
 
-        compare_box_error_attributes(expected, actual, expected)
-        compare_box_error_attributes(expected, actual, actual)
+        compare_box_error_attributes(expected, actual)
 
         if (expected.prev ~= nil) or (actual.prev ~= nil) then
             return compare_box_errors(expected.prev, actual.prev)