[Twig] allow to use string phone numbers in templates filters

[oleg-andreyev]

When working with any templating enging in most cases we work with string and objects.

This PR allows using string for Twig filters.

[Nek-]

Hello @oleg-andreyev , thank you very much for your contribution, it's extremely relevant. Could you please however take a look at this? I'd like also @maxhelias @jderusse @odolbeau to have a look to my comment if possible.

[maxhelias]

Thanks @oleg-andreyev ! :)