Fix non-static methods called as static '::' methods

[Ayesh]

Fixes a couple static calls in TableParser class that used static method call pattern (::) on non-static calls ('->`).

Thank you.

[GrahamCampbell]

I think the bug is that the method is not static, not that it is called wrong? The method should instead be changed to be static.

[Ayesh]

Hi @GrahamCampbell - Thanks for the review.
parseCell is a private method and TableParser is declared final, but parseCell method uses instance properties ($this->columns) so I propose that we change the call to a non-static call.

[GrahamCampbell]

Oh, yeh.

[colinodell]

Thanks for the fix!