fix(google-tag-manager): fix respectDoNotTrack

[LaurentTreguier]

The condition for initializing page tracking doesn't work properly:

!this.options.respectDoNotTrack && this.options.pageTracking && !this.hasDNT()

Using && everywhere means that setting respectDoNotTrack to true will prevent the entire condition from ever resolving to true, even if the user does not have the "do not track" setting to true.
Setting respectDoNotTrack to true means that the condition will only resolve to true if the user disables "dot not track" (and thus means that the user's "do not track" setting is then respected)

[pi0]

Thanks!