Fix autosave issues for MR discussions

Fixes multiple autosave issues and ESC confirmations around noteable shared components and new MR discussions.

Fixes autosave issue in noteable shared components

Fixes ESC confirmation and autosave issues in reply a discussion form

Adds ESC confirmation to new discussion form

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/48876 and https://gitlab.com/gitlab-org/gitlab-ce/issues/48877