Delivery format: Support the format field on the trigger delivery spec

[Cali0707]

Problem
To allow for specifying the cloudevent format when delivering events from a trigger, we should support the format field on the delivery spec of the trigger. Specifically we will need to:

1. Add the field to the CRD
2. Depending on the value of the field, correctly configure the kncloudevents dispatcher in the broker filter component to send the cloudevent with the correct binding

Persona:
Which persona is this feature for?

Exit Criteria
An e2e test indicating that triggers deliver events with the correct format (structured, binary, input)

Time Estimate (optional):
How many developer-days do you think this may take to resolve? 1-2

Additional context (optional)
Add any other context about the feature request here.

• Parent issue: Delivery Format: support specifying the event format #8057

[Cali0707]

/triage accepted

[Cali0707]

/help
Note that this needs #8074 and #8075 resolved before it can be worked on

[knative-prow]

@Cali0707:
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In response to this:

/help
Note that this needs #8074 and #8075 resolved before it can be worked on

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[Cali0707]

/assign