fix(dropdown): values are incorrect if they contain some special chars

[lubber-de]

Description

Dropdown values which are supposed to be encoded into htmlentities like < were wrongly encoded whenever the values changed. Especially when working with mulitple selection dropdowns.
Reason for this was the overseen fact that an ampersand & was also encoded into &. As htmlentities are in general encoded by starting with an ampersand aswell this was totally messing up the value string.

As the escape routine was also implemented in other modules, this PR fixes the logic there as well

Testcase

Broken

https://jsfiddle.net/4cqtnf0d/

Fixed

https://jsfiddle.net/yfgwph04/

Screenshot

Before	After

Closes

#1207

[y0hami]

LGTM

[exoego]

XML-like values (e.g. <abc>) are not rendered in dropdown both in current and this PR.
Is this as-designed for some reason?
https://jsfiddle.net/2cp5gL7o/

Since < and > are rendered in dropdown, I think <xml-like> should be rendered too.
This might be trickier, so could be addressed in later.

[lubber-de]

Since < and > are rendered in dropdown, I think <xml-like> should be rendered too.
This might be trickier, so could be addressed in later.

@exoego <xml> is valid html, thus it's parsed and used as such by default. If you want to display such html code, it works by using preserveHTML:false
See https://jsfiddle.net/uLejd364/1/

[lubber-de]

@hammy2899 I had to fix the remove label selection as @GammaGames mentioned , so please review again. I updated the jsfiddle in the description accordingly https://jsfiddle.net/uLejd364/

[exoego]

LGTM
Now I knew preserverHTMl option.

[lubber-de]

@exoego @hammy2899 Please review again, i also fixed the situation when allowAdditions: true was set (entries came up twice then... 🙄 )
See here:

Broken

https://jsfiddle.net/wckbtaey/

Fixed

https://jsfiddle.net/wckbtaey/1/

[y0hami]

LGTM

[exoego]

LGTM

[prudho]

LGTM