20.7
```
SELECT indexOf(['a', 'b', 'c'], toLowCardinality('a'))

┌─indexOf(['a', 'b', 'c'], toLowCardinality('a'))─┐
│                                               1 │
└─────────────────────────────────────────────────┘
```

20.8
```
SELECT indexOf(['a', 'b', 'c'], toLowCardinality('a'))


Received exception from server (version 20.8.3):
Code: 43. DB::Exception: Received from localhost:9000. DB::Exception: Types of array and 2nd argument of function "indexOf" must be identical up to nullability, cardinality, numeric types, or Enum and numeric type. Passed: Array(String) and LowCardinality(String).. 
```

https://github.com/ClickHouse/ClickHouse/pull/12550

/cc @myrrc 

const bool arg_lc_inner_type_is_nullable = arg_is_lc && arg_lc_inner_type->isNullable();
        if (array_is_lc) 
        {
            const DataTypePtr array_lc_nested_or_lc_nullable_nested = array_lc_inner_type_is_nullable
                ? checkAndGetDataType<DataTypeNullable>(array_lc_inner_type.get())->getNestedType()
                : array_lc_inner_type;
            if (arg_is_lc) 
            {
                const DataTypePtr arg_lc_nested_or_lc_nullable_nested = arg_lc_inner_type_is_nullable
                    ? checkAndGetDataType<DataTypeNullable>(arg_lc_inner_type.get())->getNestedType()
                    : arg_lc_inner_type;
                return allowNested(
                        array_lc_nested_or_lc_nullable_nested,
                        arg_lc_nested_or_lc_nullable_nested);
            }
            else if (arg_is_nullable) 
            {
                if (!array_lc_inner_type_is_nullable)
                    return false; 
                return allowNested(
                        array_lc_nested_or_lc_nullable_nested,
                        arg_or_arg_nullable_nested);
            }
            else 
                return allowNested(array_lc_nested_or_lc_nullable_nested, arg);
        }
        return false;
    }
#define INTEGRAL_TPL_PACK UInt8, UInt16, UInt32, UInt64, Int8, Int16, Int32, Int64, Float32, Float64
    void executeOnNonNullable(ColumnsWithTypeAndName & columns, const ColumnNumbers & arguments, size_t result) const