Import-db fix for new pruning storers

[iulianpascalau]

• fixed import-db process when opening storers in advance: open the pruning storers in order with no gaps

[codecov]

Codecov Report

Merging #3733 (ce5fb7e) into development (1743465) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##           development    #3733   +/-   ##
============================================
  Coverage        73.65%   73.65%           
============================================
  Files              599      599           
  Lines            79149    79150    +1     
============================================
+ Hits             58300    58301    +1     
  Misses           16262    16262           
  Partials          4587     4587           

Impacted Files	Coverage Δ
dataRetriever/storageResolvers/headerResolver.go	90.78% <100.00%> (+0.12%)	⬆️

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[gabi-vuls]

System test passed.