fix(core 8.2): Parse template literal syntax with nested identifiers as expression

[CatchABus]

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What is the current behavior?

This is a change that came up due to expression parser rework and its new features.
NativeScript Core cannot parse XML expression with template literal syntax and nested indentifiers.
Example:

<Page actionBarHidden="true" xmlns="http://www.nativescript.org/tns.xsd">
    <GridLayout>
        <Label text="{{ 'Hello' + username }}"/> <!-- Works -->
        <Label text="{{ `Hello ${username}` }}"/> <!-- Only identifier 'username' will be parsed -->
    </GridLayout>
</Page>

What is the new behavior?

Template literal syntax that includes identifiers will be parsed as expression.