[Epic] Issues during integration from source plugins

[zhongnansu]

this is an epic for all issues reported from other source plugin(Alerting, Reporting, etc) during the development of integration to notification

• [BUG] Support Email credentials from Alerting #230
• [BUG] Can't send custom webhooks #245
• [BUG] Support HOST_DENY_LIST for destinations #247
• [BUG] Uncaught exception in sendNotification #246
• [BUG] Support new lines in chime message notification #238
• [BUG] Notification plugin hangs at PluginBaseAction class #233
• Support PUT and PATCH method types as well for Webhook type #219
• [BUG] Subjects not supported for notifications #226
• Support backend role filtering for notification channels #220
• [BUG] No support for http urls in notification channels #232

more issues

• [BUG] Send Notification API does not send failure to send response #256
• [BUG] Support search query on Notification Configs for Alerting support #255
• Support a pass through internal API for ISM #253
• Add support for other plugins to use notifications without requiring a code change #262

[qreshi]

Closing this issue since Alerting and ISM have successfully integrated with Notifications.