Fixes #20461 - csv_exporter results in empty rows

[sjha4]

While trying to extend csv export functionality to katello pages, we observed that the csv_exporter was rendering empty rows in the exported csv.
The root cause is the line "columns.map!{|c| c.to_s.split('.').map(&:to_sym)}" getting executed more than once in the enumerator block causing the column names to be prepended with multiple ' : '

[mention-bot]

@sjha4, thanks for your PR! By analyzing the history of the files in this pull request, we identified @tbrisker to be a potential reviewer.

[theforeman-bot]

Issues: #20461

[tbrisker]

While the change itself seems harmless to me, I'm curious why on certain pages the enumerator is created multiple times? This may be an indicator of some deeper issue, since on most pages this works without a problem.

[sjha4]

@tbrisker : To put this into context, I tried this for the PR: Katello/katello#6889

[xprazak2]

@sjha4, I think this has been fixed already as map! was replaced with
map. Could you re-test if the issue still present?

[sjha4]

Hey @xprazak2 : Tested this on a recent PR in katello around csv export. I do not see this issue anymore.
I will go ahead and close this PR.