Invite can be sent to same email address that is pending approval

- can be re-phrased as a user story
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**Describe the bug in current/ situation**
Owner was able to send invite to an email address that had already joined the account

**Impact of this bug**
Describe the impact, i.e. what the impact is, and number of users impacted.

**Pre Conditions (which Env, any pre-requesites or assumptions to execute steps?**
Member has accepted the invitation and owner has gotten the notification for the same in pending approval tab

**Steps to Reproduce**
Steps to reproduce the behavior:
1. As an owner, Go to 'Team Members'
2. Click on 'Invite people'
3. Add email address same as the user who had already joined the account

**Actual/ observed behavior/ results**
Member accepts the invitation and owner is able to see the notification in pending approval tab. However, use can send invite to the same email id again.

**Expected behavior**
System should show error message that invite is pending approval or duplicate email id or anything else that is relevant.

**Screenshots/ Visual Reference/ Source**
![Screen Shot 2020-02-21 at 8.17.58 AM.png]
* Link to the User Story (that relates to the bug)