CustomAttribute is not being evaluated when on or inside an if.bind-Element

**I'm submitting a bug report**

* **Library Version:**
1.10.3

**Please tell us about your environment:**
* **Operating System:**
Windows 10

* **Node Version:**
10.13.0

* **NPM Version:**
6.12.0

* **JSPM OR Webpack AND Version**
It's an Aurelia Plugin created using the CLI. It's using gulp based build with npm

* **Browser:**
all

* **Language:**
TypeScript 3

**Current behavior:**
> I'm not sure whether it's plugin specific or a general issue, I haven't had the time to test it in a normal app.
1. Create a custom attribute
2. Register the custom attribute in global resources
3. Create a custom component / element
4. create an element (i.e. div) with an if.bind attribute, make the condition initially false
5. add the custom attribute to the same element or any child element of it.
6. start the application, the custom attribute won't be evaluated
7. make the if.bind-condition somehow true using a button or timeout
8. the element get's shown but the custom attribute is still not being evaluated.

If the attribute is on an element with initally true for if.bind or a generally visible element, it is working fine.

* **What is the expected behavior?**
The custom attribute should be evaluated / applied / bound / executed even on toggled elements using if.bind

* **What is the motivation / use case for changing the behavior?**
We should be able to hide complex element structures from the DOM and still be able to use custom attributes.

Reproduce the seven-step case in an Aurelia TypeScript application, using a globally registered custom attribute on and inside an element controlled by if.bind. Compare initially visible and initially hidden elements, then verify that toggling the condition evaluates, applies, and binds the custom attribute as expected.

Written by the indexing model from the issue text.