Fail YarnAppLaunch if there's existing AM with configuration

[autumnust]

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-XXX

Description

• [ ] Here are some details about my PR, including screenshots (if applicable):

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-io]

Codecov Report

Merging #2936 into master will increase coverage by 0.00%. The diff coverage is 0.00%.

@@            Coverage Diff            @@
##             master    #2936   +/-   ##
=========================================
  Coverage     44.60%   44.61%           
  Complexity     8980     8980           
=========================================
  Files          1936     1936           
  Lines         73234    73238    +4     
  Branches       8083     8085    +2     
=========================================
+ Hits          32669    32676    +7     
+ Misses        37515    37508    -7     
- Partials       3050     3054    +4     

Impacted Files	Coverage Δ	Complexity Δ
...rg/apache/gobblin/yarn/GobblinYarnAppLauncher.java	20.96% <0.00%> (-0.21%)	8.00 <0.00> (ø)
...lin/util/filesystem/FileSystemInstrumentation.java	85.71% <0.00%> (-7.15%)	3.00% <0.00%> (ø%)
...ava/org/apache/gobblin/fsm/FiniteStateMachine.java	73.48% <0.00%> (-3.04%)	18.00% <0.00%> (-3.00%)
...lin/restli/throttling/ZookeeperLeaderElection.java	70.00% <0.00%> (-2.23%)	13.00% <0.00%> (ø%)
...lin/elasticsearch/writer/FutureCallbackHolder.java	61.42% <0.00%> (-1.43%)	4.00% <0.00%> (ø%)
.../apache/gobblin/runtime/api/JobExecutionState.java	80.37% <0.00%> (+0.93%)	24.00% <0.00%> (ø%)
...in/java/org/apache/gobblin/cluster/HelixUtils.java	41.73% <0.00%> (+3.47%)	15.00% <0.00%> (+1.00%)
...e/gobblin/runtime/app/ServiceBasedAppLauncher.java	49.51% <0.00%> (+9.70%)	12.00% <0.00%> (+2.00%)

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[jhsenjaliya]

LGTM from the functionality perspective, pls look at the comment though.