Fix issue where org level user lists shows space roles from other orgs

[richard-cox]

• blocked on Scale Users in CF Summary section #3371
• To reproduce..
  • user1 is user of org1, org2 and space dev in org1's space1
  • user2 is user of org1, org2 and space dev in org2's space1
  • connect to cf using user1 and navigate to org2's users list
  • user1 space cell showns their space role from org1
• Explenation
  • user1 cannot see org2's space, so should not see any space roles at org2 level
  • cell receives a list of spaces that it should show roles for
  • empty spaces list for user1 in org2 was being converted to null
  • cell therefore thought it should show all of users spaces
• I've tracked this change back and it was in from the start of the user pill with space prefix work
• Have tested with
  • admin who can see all users and their roles at cf, org and space level
  • user2 who has limited visibility of spaces at org and space levels (no cf users table for non-admins)

[cfdreddbot]

✅ Hey richard-cox! The commit authors and yourself have already signed the CLA.

[codecov]

Codecov Report

Merging #3399 into v2-master will decrease coverage by <.01%.
The diff coverage is 33.33%.

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##           v2-master   #3399      +/-   ##
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- Coverage      70.31%   70.3%   -0.01%     
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  Files            693     693              
  Lines          30727   30727              
  Branches        6995    6994       -1     
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- Hits           21606   21604       -2     
- Misses          9121    9123       +2