[fleet] Fix apm package types

[simitt]

Motivation/summary

Update apm package to use types supported by the package-spec

• text over string
• integer over int

Related issues

fixes #elastic/package-storage#1011

[codecov-io]

Codecov Report

Merging #4931 (f9c32a9) into master (09cbdea) will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4931      +/-   ##
==========================================
+ Coverage   77.05%   77.07%   +0.01%     
==========================================
  Files         172      172              
  Lines       10284    10284              
==========================================
+ Hits         7924     7926       +2     
+ Misses       2360     2358       -2     

Impacted Files	Coverage Δ
beater/jaeger/common.go	91.66% <0.00%> (+8.33%)	⬆️

[apmmachine]

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Build stats

• Build Cause: Pull request #4931 opened

• Start Time: 2021-03-09T08:44:45.033+0000

• Duration: 39 min 12 sec

• Commit: f9c32a9

Test stats 🧪

Test	Results
Failed	0
Passed	4770
Skipped	117
Total	4887

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