[Analytics] Support lazy module without declarations field

[GrandSchtroumpf]

Version info

Angular: 9.0.1 Firebase: 7.. AngularFire: 6.0.0-rc1

How to reproduce these conditions

• Import AngularFireAnalyticsModule in AppModule.
• Lazy load a module without declarations field.

Debug output

Cannot read annotations of undefined

How to solve

Modify this line :

const selectors = [].concat.apply([], declarations.map(...))

Becomes :

const selectors = [].concat.apply([], (declarations || []).map(...))

[jamesdaniels]

Thanks for the report! I'll turn a fix around quickly.