xCluster: Update Cluster check to account for Paused Nodes

[OxHobbs]

Pull Request (PR) description

Updated the cluster membership check to return true if the node is paused. Added a localized string/verbose message to state the node is 'Paused' during the test method.

This Pull Request (PR) fixes the following issues

Fixes #201

Task list

• [x] Update the Test method to account for joined nodes in a 'Paused' state.
• [x] Add a localized string/verbose message to state the node is already joined to the cluster and is in a 'Paused' state.
• [x] Add unit test for the new condition of a 'paused' node in cluster.

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This change is 

[codecov-io]

Codecov Report

Merging #202 into dev will not change coverage. The diff coverage is 100%.

@@         Coverage Diff         @@
##            dev   #202   +/-   ##
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  Coverage   100%   100%           
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  Files         8      8           
  Lines       493    496    +3     
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+ Hits        493    496    +3