issue #45: fix failing unit tests

[dmitriim]

Fixes #45

The test is relying on a core template. As part of applying https://moodle.atlassian.net/browse/MDL-85040 an extra space was removed from the core icon template.

This fix aligns the test to a new core code.

After applying the patch:

Moodle 4.5.6+ (Build: 20250815), e07cf88f4d88c2ebe39606ad9fcf4f6b7affab3a
Php: 8.3.24, pgsql: 17.6 (Debian 17.6-1.pgdg13+1), OS: Linux 6.14.0-27-generic x86_64
PHPUnit 9.6.18 by Sebastian Bergmann and contributors.

.......                                                             7 / 7 (100%)

Time: 00:01.850, Memory: 76.50 MB

OK (7 tests, 16 assertions)
root@95fd2fd4bfb0:/var/www/moodle45#

[dmitriim]

@timhunt hey! Any chance you can review this fix?