Explicitly sets replicas and shards to 1 for ISM history indices

[dbbaughe]

Issue #, if available:

Description of changes:
Explicitly sets replicas and shards to 1 for ISM history indices

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 #318 (6da842e) into master (cff965e) will decrease coverage by 0.06%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master     #318      +/-   ##
============================================
- Coverage     75.75%   75.69%   -0.07%     
  Complexity      874      874              
============================================
  Files           123      123              
  Lines          4537     4538       +1     
  Branches        677      677              
============================================
- Hits           3437     3435       -2     
- Misses          731      732       +1     
- Partials        369      371       +2     

Impacted Files	Coverage Δ	Complexity Δ
...icsearch/indexmanagement/IndexManagementIndices.kt	62.06% <100.00%> (+0.66%)	10.00 <0.00> (ø)
...ndexstatemanagement/IndexStateManagementHistory.kt	75.96% <100.00%> (ø)	27.00 <0.00> (ø)
...nt/indexstatemanagement/model/destination/Slack.kt	40.90% <0.00%> (-13.64%)	2.00% <0.00%> (-2.00%)
...dexstatemanagement/elasticapi/ElasticExtensions.kt	61.53% <0.00%> (-5.77%)	0.00% <0.00%> (ø%)
...nt/indexstatemanagement/model/destination/Chime.kt	54.54% <0.00%> (+13.63%)	4.00% <0.00%> (+2.00%)

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[thalurur]

Just curious, what is it set to without this explicit declaration?

[dbbaughe]

@thalurur default is 1p/1r, except on our managed service where it's still 1p/5r.