* cmd/k8s-operator,k8s-operator/sessonrecording: ensure CastHeader contains terminal size
For tsrecorder to be able to play session recordings, the recording's
CastHeader must have '.Width' and '.Height' fields set to non-zero.
Kubectl (or whoever is the client that initiates the 'kubectl exec'
session recording) sends the terminal dimensions in a resize message that
the API server proxy can intercept, however that races with the first server
message that we need to record.
This PR ensures we wait for the terminal dimensions to be processed from
the first resize message before any other data is sent, so that for all
sessions with terminal attached, the header of the session recording
contains the terminal dimensions and the recording can be played by tsrecorder.
Updates tailscale/tailscale#19821
Signed-off-by: Irbe Krumina <irbe@tailscale.com>
8e1c00f841