RIKEN: Separator tuning, update trace even if value stays the same

[zsoltkebel]

Feedback from IS:

"... bug where if a value hasn’t changed it doesn’t draw anything, and when it eventually changes it draws a diagonal from the last point it plotted to this new point."

Acceptance criteria:

• Change traces to update on trigger or value change

[zsoltkebel]

PRs

• Add heartbeat for traces' x PV ibex_gui#1601
• Ticket8002 #8019

[zsoltkebel]

Now patched on RIKENFE