[Test] Enable displayDetailsOnTestsThatTriggerWarnings to true in tests to show warning

[samsonasik]

To properly show erorrs:

vendor/bin/phpunit tests/Issues                                                                           
PHPUnit 10.1.3 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.2.5
Configuration: /Users/samsonasik/www/rector-src/phpunit.xml

...............................................................  63 / 179 ( 35%)
.............W..W.............................................. 126 / 179 ( 70%)
.....................................................           179 / 179 (100%)

Time: 00:19.685, Memory: 1.18 GB

2 tests triggered 2 PHP warnings:

1) Rector\Core\Tests\Issues\Issue6496\AutoImportDocBlockTest::test with data set #1
Undefined array key 0
/Users/samsonasik/www/rector-src/rules/CodingStyle/Application/UseImportsAdder.php:119

/Users/samsonasik/www/rector-src/tests/Issues/Issue6496/AutoImportDocBlockTest.php:14

2) Rector\Core\Tests\Issues\Issue6496\AutoImportDocBlockTest::test with data set #2
Undefined array key 0
/Users/samsonasik/www/rector-src/rules/CodingStyle/Application/UseImportsAdder.php:119

/Users/samsonasik/www/rector-src/tests/Issues/Issue6496/AutoImportDocBlockTest.php:14

OK, but there are issues!
Tests: 179, Assertions: 191, Warnings: 2.

Ref rectorphp/rector#7958

[samsonasik]

@TomasVotruba Fixed 🎉

[samsonasik]

It seems also happen in other rector packages, I will enable in them.