Revert gen protos to xmtp/protos:main branch

[fbac]

Last week a PR introduced a branch change in dev/gen/protos without us noticing, making us not receive any further proto update. Revert it.

[graphite-app]

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[macroscopeapp]

Revert protobuf generation to use main branch instead of feature branch and update generated protocol buffer files with new event backup functionality and welcome message encryption algorithms

Changes the protobuf generation script to use the main branch of xmtp/proto repository instead of the 05-12-change_attestation_signature_format feature branch, resulting in updated generated files across the codebase:

• Updates dev/gen/protos script to generate from main branch
• Adds new BACKUP_ELEMENT_SELECTION_EVENT enum value and Event field to BackupElement message in pkg/proto/device_sync/device_sync.pb.go
• Creates new pkg/proto/device_sync/event_backup.pb.go with EventSave message type and EventLevelSave enum for event backup functionality
• Adds WrapperAlgorithm and MessageCursor fields to WelcomeMessage_V1 and WelcomeMessageInput_V1 structures in pkg/proto/mls/api/v1/mls.pb.go
• Adds WelcomeWrapperAlgorithm field to PostCommitAction_Installation structure in pkg/proto/mls/database/intents.pb.go
• Updates OpenAPI specifications in pkg/proto/openapi/mls/api/v1/mls.swagger.json and pkg/proto/openapi/xmtpv4/payer_api/payer_api.swagger.json with new WelcomeWrapperAlgorithm enum including post-quantum encryption algorithm XWING_MLKEM_768_DRAFT_6

📍Where to Start

Start with the protobuf generation script in dev/gen/protos to understand the source change from feature branch to main branch.

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Macroscope summarized 54dd4cd.