[GOBBLIN-1872] Enable scheduler for non-leader in multi-active scheduler configuration

[umustafi]

Dear Gobblin maintainers,

Please accept this PR. I understand that it will not be reviewed until I have checked off all the steps below!

JIRA

• My PR addresses the following Gobblin JIRA issues and references them in the PR title. For example, "[GOBBLIN-XXX] My Gobblin PR"
  • https://issues.apache.org/jira/browse/GOBBLIN-1872

Description

• Here are some details about my PR, including screenshots (if applicable):
  Set scheduler to active for all hosts when multi-active scheduler is enabled to allow hosts to use multi-active lease arbiter to handle flow triggers and ensure no missed flows and zero downtime.

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:

Commits

• My commits all reference JIRA issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

[codecov-commenter]

Codecov Report

Merging #3736 (5a9b3d0) into master (af48b31) will increase coverage by 0.00%.
Report is 2 commits behind head on master.
The diff coverage is 33.33%.

@@            Coverage Diff            @@
##             master    #3736   +/-   ##
=========================================
  Coverage     47.08%   47.09%           
- Complexity    10862    10866    +4     
=========================================
  Files          2146     2146           
  Lines         84781    84795   +14     
  Branches       9408     9411    +3     
=========================================
+ Hits          39922    39933   +11     
  Misses        41238    41238           
- Partials       3621     3624    +3     

Files Changed	Coverage Δ
...in/service/modules/core/GobblinServiceManager.java	47.54% <33.33%> (-0.55%)	⬇️

... and 5 files with indirect coverage changes

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