Client-side error thrown when reading plugin settings

[mickmister]

I can't consistently reproduce, but I was getting an error where pluginSettings was null/undefined in the below code, and so accessing security_level_empty_for_jira_subscriptions was throwing an error

mattermost-plugin-jira/webapp/src/components/modals/channel_subscriptions/index.ts

Line 48 in 17e8a47

const securityLevelEmptyForJiraSubscriptions = pluginSettings.security_level_empty_for_jira_subscriptions;