Fix filter by user.backendroles and integ tests for it

[skkosuri-amzn]

Issue #, if available:

Fix filter by user.backendroles and integ tests for it
Description of changes:

Fix filter by user.backendroles and integ tests for it

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

Merging #290 into master will decrease coverage by 0.29%.
The diff coverage is 63.63%.

@@             Coverage Diff              @@
##             master     #290      +/-   ##
============================================
- Coverage     80.47%   80.17%   -0.30%     
  Complexity      196      196              
============================================
  Files           151      151              
  Lines          5146     5165      +19     
  Branches        668      673       +5     
============================================
  Hits           4141     4141              
- Misses          654      668      +14     
- Partials        351      356       +5     

Impacted Files	Coverage Δ	Complexity Δ
...rch/alerting/transport/TransportGetAlertsAction.kt	75.38% <0.00%> (ø)	0.00 <0.00> (ø)
...erting/transport/TransportGetDestinationsAction.kt	76.05% <0.00%> (ø)	0.00 <0.00> (ø)
...alerting/transport/TransportSearchMonitorAction.kt	58.33% <0.00%> (ø)	0.00 <0.00> (ø)
...troforelasticsearch/alerting/util/AlertingUtils.kt	66.66% <54.54%> (-33.34%)	0.00 <0.00> (ø)
...rting/transport/TransportIndexDestinationAction.kt	56.52% <100.00%> (+1.56%)	0.00 <0.00> (ø)
.../alerting/transport/TransportIndexMonitorAction.kt	60.00% <100.00%> (+0.90%)	0.00 <0.00> (ø)
...roforelasticsearch/alerting/alerts/AlertIndices.kt	66.14% <0.00%> (-9.45%)	0.00% <0.00%> (ø%)
...distroforelasticsearch/alerting/core/JobSweeper.kt	71.65% <0.00%> (-0.54%)	35.00% <0.00%> (ø%)
...endistroforelasticsearch/alerting/MonitorRunner.kt	78.00% <0.00%> (-0.41%)	0.00% <0.00%> (ø%)

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