Enable hostname monitoring on Ubuntu

[jithinjosepkl]

Description

Issue #2645

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PR information

• The title of the PR is clear and informative.
• There are a small number of commits, each of which has an informative message. This means that previously merged commits do not appear in the history of the PR. For information on cleaning up the commits in your pull request, see this page.
• If applicable, the PR references the bug/issue that it fixes in the description.
• New Unit tests were added for the changes made

Quality of Code and Contribution Guidelines

• I have read the contribution guidelines.

Fixes #2645

[codecov]

Codecov Report

Merging #2647 (a156dd0) into master (e4cba48) will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2647      +/-   ##
==========================================
+ Coverage   71.94%   71.97%   +0.02%     
==========================================
  Files         101      101              
  Lines       15075    15075              
  Branches     2396     2396              
==========================================
+ Hits        10846    10850       +4     
+ Misses       3746     3743       -3     
+ Partials      483      482       -1     

Impacted Files	Coverage Δ
azurelinuxagent/ga/collect_telemetry_events.py	90.06% <0.00%> (-1.37%)	⬇️
azurelinuxagent/ga/update.py	88.81% <0.00%> (+0.33%)	⬆️
azurelinuxagent/common/persist_firewall_rules.py	83.43% <0.00%> (+2.95%)	⬆️

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