[Php80] Fix end slash regex on AttributeValueResolver

[samsonasik]

\r? end cause mac os new line detected, it will allow:

some with \

which should not.

[samsonasik]

also updated explode to use our NewLineSplitter to ensure windows \r\n new line included on explode, not part of existing line that cause left over \r

[samsonasik]

I added test for it, if after \, no new line, then keep it as a character, also add test for with new line without other text

[samsonasik]

All checks have passed 🎉 @TomasVotruba I am merging it ;)