[Admin] Verify that field 'Прізвище' accepts '=<50' of valid data

**Priority:** high

**Preconditions**
1. The "StreetCode page" is opened.
3. Logged as admin.

**Steps to reproduce**
1. Click 'Новий стріткод'.
2. Fill a field 'Номер стріткоду', click 'Перевірити'.
3. Popover window appears "Ще жоден стріткод немає такого номеру. Можете з впевненістю його використовувати."
4. Fill a field 'Прізвище' with "=<50" symbols.

| Pass/Fail | Expected result | Data |
|--------|--------|--------|
| | The field is filled | Михайло Драгоманов |
| | The field is filled | Михайло Драгоманов Михайло Драгоманов Михайло Драг |
| | The field is filled | М |
| | The field is filled | Mykhailo Drahomanov |
| | The field is filled | Mykhailo Drahomanov Mykhailo Drahomanov Mykhailo D |
| | The field is filled | D |
| | The field is filled | Михайло Драгоманов 0 |
| | The field is filled | Михайло Драгоманов {}":> |
| | The number of characters has been reduced to 50 by the system | Mykhailo Drahomanov Mykhailo Drahomanov Mykhailo Dr |
| | The number of characters has been reduced to 50 by the system | Mykhailo Drahomanov Mykhailo Drahomanov Mykhailo Drahoma Mykhailo Drahomano |

6. Fill in other mandatory fields with valid data.
7. Click 'Опублікувати'.

**Expected result**
New StreetCode with valid data in 'Прізвище' will be published, with invalid data will not be published.

**User story:** #115
**Test Case:** #429

**Related bug:**