Update SaltBrowser.coffee to Provide Better Error Display to User

[dalejerikson]

The following was sourced from this GitHub issue filed by John McNeil: #1117

Expected Behavior

When you open the CmpdReg Salts browser, click Create New Salt and enter a duplicate salt, you should receive an error that the salt exists

Previous Behavior

Follow the above steps, then the form clears and shows this
An error occured creating Salt . Please contact support for additional help.

The console shows:
Uncaught TypeError: this.$(...) is not a function
at Object.error (SaltBrowser.js:453:62)
at k (jquery.min.js:2:16920)
at Object.fireWith [as rejectWith] (jquery.min.js:2:17707)
at y (jquery.min.js:2:80829)
at XMLHttpRequest.d (jquery.min.js:2:86374)

Fix This PR Addresses

[brianbolt]

suggestion (if-minor): It would be good if after an error, the user could correct the issue by having a non-blocking error. As it is, the user has to refresh the entire page to correct the issue. That being said, it's fairly rare register new salts and even more rare for this error to be an issue so this should be fine.

[dalejerikson]

@brianbolt I'm going to spin out a separate ticket. In the original implementation, this error notification was part of the notification bar and was functioning normally. It was much more user friendly and would allow the user to correct their mistakes in the same window. In the example I provided below, these are warnings when I try to edit a salt. Something similar should happen with the 3 errors I show in the screenshot of my PR. This PR is quick fix but I'll need to investigate why this original implementation is broken and restore that behavior.