refactor: Fix phpstan isset offset

[neznaika0]

Description
It seems $matches always has 6 keys. In addition, other indexes are not checked - they are expected to exist.

┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ $matches                                                                                                                                                                                            │
└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
array (6) [
    0 => string (34) " j.name  LIKE :j.name: ESCAPE '!' "
    1 => string (0) ""
    2 => string (7) " j.name"
    3 => string (27) "  LIKE :j.name: ESCAPE '!' "
    4 => string (0) ""
    5 => string (0) ""
]

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[paulbalandan]

This can go to develop branch.