View Parser - Fix ParsePair() with filter

[najdanovicivan]

Description
Fixes using filters on properties in arrays

Problem is related to the use of | character in filters as | character is handled as OR in regex. This makes replace singe get multiple matches which in the end leads to multiplied data by number of | characters.

Additionally I have added test case testParsePairWithAbs in ParserFilterTest. Initially I was thinking to modify the existing tests to check for nested array elements as well. But this will require changing almost all the test methods. So I've added the new test method based on testAbs() which checks that abs filter works in various nested array properties

I've noticed some style issue. CodeSniffer replaced

if (count($keyVal) == 2)

to

if (count($keyVal) === 2)

So I also included this change in the commit

This PR Fixes #2360

Checklist:

• Securely signed commits
• Component(s) with PHPdocs
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[MGatner]

Looks great! Thanks for providing a test with it; quality PR.