[crm] Align THRESHOLD_CLEAR log message severity in HLD according to …

…implementation (#1046)

* First it was planned to have THRESHOLD_CLEAR message as NOTICE.
* But during implementation it was requested to change it to WARNING.
* In order to be consistent with THRESHOLD_EXCEEDED message which is WARNING.
* So CRM implementation has WARNING severity for both messages from day 1.
* But HLD was not update accordingly and this change updates it to be aligned.

Signed-off-by: Volodymyr Samotiy <volodymyrs@nvidia.com>

doc/crm/Critical-Resource-Monitoring-High-Level-Design.md

@@ -104,7 +104,7 @@ Monitoring process should periodically poll SAI counters for all required resour
 
 ```"<Date/Time> WARNING <Process name>: THRESHOLD_EXCEEDED for <TH_TYPE> <%> Used count <value> free count <value>"```
 
-```"<Date/Time> NOTICE <Process name>: THRESHOLD_CLEAR for <TH_TYPE> <%> Used count <value> free count <value>"```
+```"<Date/Time> WARNING <Process name>: THRESHOLD_CLEAR for <TH_TYPE> <%> Used count <value> free count <value>"```
 
 ```<TH_TYPE> = <TH_PERCENTAGE, TH_USED, TH_FREE>```