Add a "Last Synced" Timestamp to the Dashboard

[oseghalep]

Description:
On the main dashboard, display a timestamp indicating when the cost data was last refreshed for each connected cloud provider. This gives users confidence in the data's freshness.

Acceptance Criteria:

• The dashboard shows "Last synced: [time]" for each provider.
• The timestamp updates after a successful sync.

[nobledeveloper01]

i will like to pick this up

[oseghalep]

Please proceed