agent: rerun agent when failed to get status

[vyaghras]

Issue number: 568

Description of changes:
Restart the event loop for agent when the Status is not present in Bottlerocket Shadow.

Testing done:
Before change: Agent exited and restarts agent because of error Unable to operate on BottlerocketShadow: 'Unable to get Bottlerocket node 'status' because of missing 'status' value'

 2023-10-30T16:44:04.396950Z ERROR agent::agentclient: error: Unable to operate on BottlerocketShadow: 'Unable to get Bottlerocket node 'status' because of missing 'status' value'
    at agent/src/agentclient.rs:519
    in agent::agentclient::run
 
  2023-10-30T16:44:04.396986Z ERROR agent: Agent runner exited
    at agent/src/main.rs:116

After change: Restarts the event loop in agent to refetch bottlerocket_shadow containing Status.

2023-11-03T23:31:09.587781Z  WARN agent::agentclient: An error occurred when fetching BottlerocketShadowStatus. Restarting event loop
    at agent/src/agentclient.rs:555
    in agent::agentclient::run

  2023-11-03T23:33:02.788282Z  INFO agent::agentclient: Checking for Bottlerocket updates.
    at agent/src/agentclient.rs:209

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[cbgbt]

Nice work!