[Prep] EX: Stop receiving the app badge count from the homeserver

[manuroe]

Description

Implement matrix-org/matrix-spec-proposals#4076 so that the backend do not control anymore the app badge count.

It is also useful to stop having unread update pushes on Android because they are useless, could be considered as push spams and may be a reason why push gateway blocks some pushes (which means no notifications for the end user)

Acceptance criteria

• The app badge count on EXI is not more updated by the homeserver
• EXA does not receive anymore unread update pushes that are useless on Android

Size estimate

S

Dependencies

• None

Out of scope

Subtasks

Android

• [Task] Stop receiving the app badge count from the homeserver element-x-android#5316

iOS

• [Task] Stop receiving the app badge count from the homeserver  element-x-ios#3572

SDK

• Ruma implementation of disable_badge_count: client-api: Add disable_badge_count to the set pusher request ruma/ruma#2214
• Add disable_badge_count parameter to the set_pusher method. matrix-org/matrix-rust-sdk#4951

MSC

• MSC4076: Let E2EE clients calculate app badge counts themselves (disable_badge_count) matrix-org/matrix-spec-proposals#4076

Synapse

• MSC4076: Add disable_badge_count to pusher configuration synapse#17975
• /client/versions: Advertise MSC4076: Add disable_badge_count to pusher configuration synapse#18930

Other

• Enable MSC4076 in beta.matrix.org for end to end testing
• Done in ESS and m.org, ie make MSC4076 enabled

[manuroe]

EDIT: I updated this prep story to include Android in order to reduce push bandwidth and reduce the risk of push requests being ignored by the push gateways.

[manuroe]

@jmartinesp will do the implementation client side: Ruma --> SDK --> EXA.

[manuroe]

With element-hq/synapse#18930, we should be able to use MSC4076 end to end. It will be enabled first on beta.matrix.org.

[manuroe]

After an internal discussion, we decided to manage the configuration at the Sygnal instance configuration level. It means matrix-org/matrix-spec-proposals#4076 is no more involved in the plan. We close this tech story in favour of #3014.