Fix ping monitor interval reset issue

Fixes #6657

Problem:
When users set a ping monitor interval below the calculated minimum
(based on ping configuration) and confirmed the warning, the interval
was being reset back to a higher value after saving. This happened
because finishUpdateInterval() was automatically adjusting the interval
when monitor data was reloaded from the server after save.

Solution:
Added isLoadingMonitor flag to track when monitor data is being loaded
vs when user is actively editing. The automatic interval adjustment in
finishUpdateInterval() now skips when:
1. Monitor data is being loaded from server (isLoadingMonitor=true)
2. User has explicitly edited the interval (editedValue=true)

This ensures that user-confirmed low intervals are respected and not
automatically increased during the save/reload cycle.

Changes:
- Added isLoadingMonitor flag to component data
- Set flag during init() when loading monitor data
- Clear flag after monitor data is fully loaded using nextTick()
- Updated finishUpdateInterval() to check both flags before auto-adjusting

src/pages/EditMonitor.vue

@@ -2393,6 +2393,7 @@ export default {
                 confirmed: false,
                 editedValue: false,
             },
+            isLoadingMonitor: false,
         };
     },
 
@@ -2915,6 +2916,7 @@ message HealthCheckResponse {
                             }
                         }
 
+                        this.isLoadingMonitor = true;
                         this.monitor = res.monitor;
 
                         if (this.isClone) {
@@ -2958,6 +2960,11 @@ message HealthCheckResponse {
                                 this.monitor.timeout = ~~(this.monitor.interval * 8) / 10;
                             }
                         }
+
+                        // Reset loading flag after all reactive updates
+                        this.$nextTick(() => {
+                            this.isLoadingMonitor = false;
+                        });
                     } else {
                         this.$root.toastError(res.msg);
                     }
@@ -3314,8 +3321,11 @@ message HealthCheckResponse {
                 // Calculate the minimum required interval based on ping configuration
                 const calculatedPingInterval = this.calculatePingInterval();
 
-                // If the configured interval is too small, adjust it to the minimum required value
-                if (this.monitor.interval < calculatedPingInterval) {
+                // Don't auto-adjust interval when:
+                // 1. Loading monitor data from server (isLoadingMonitor flag)
+                // 2. User explicitly edited the interval value (editedValue flag)
+                // This respects the user's choice of low intervals they've confirmed
+                if (!this.isLoadingMonitor && !this.lowIntervalConfirmation.editedValue && this.monitor.interval < calculatedPingInterval) {
                     this.monitor.interval = calculatedPingInterval;
 
                     // Notify the user that the interval has been automatically adjusted