Return Token value after url-encoding.

[silsha]

Q	A
Bug fix?	Y
New feature?	N
Automated tests included?	N
Related user documentation PR URL	N
Related developer documentation PR URL	N
Issues addressed (#s or URLs)	#6077
BC breaks?	Y
Deprecations?	N

Description:

From the addressed issue:

When using a token like {contactfield=company|true}, the default value |true has two different uses:

1. When the value true is set as default value, the contactfield is url-encoded and
2. When there is no value, Mautic will output the default value (true).

This results in a situation, where you can't enable url-encoding and have an empty default value at the same time.

Steps to reproduce the bug:

1. Create two new contacts – one with a company (Foo & Bar Inc.) and one without a company.
2. Send both contacts a mail including the token {contactfield=company|true}
   One contact will receive the string Foo+%26+Bar+Inc., the other one will receive true.

Steps to test this PR:

1. Create two new contacts – one with a company (Foo & Bar Inc.) and one without a company.
2. Send both contacts a mail including the token {contactfield=company|true}
   One contact will receive the string Foo+%26+Bar+Inc., the other one will receive an empty string.

List backwards compatibility breaks:

1. It's no longer possible to use true as default value.

[npracht]

Label: Bug

[galvani]

I have verified it is working. @silsha please update to current staging. Thank you.

[silsha]

@galvani I've merged staging into my branch. 👍

[galvani]

Works as suggested.

[silsha]

@galvani You don’t seem to have write access (anymore?), so your review doesn’t count towards mergeability.