[Backport 2.x] dispatch ML task to ML node first

[opensearch-trigger-bot]

Backport 6cbb626 from #346

[codecov-commenter]

Codecov Report

Merging #347 (58e2c97) into 2.x (0573bb7) will increase coverage by 0.09%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##                2.x     #347      +/-   ##
============================================
+ Coverage     92.00%   92.09%   +0.09%     
- Complexity      518      519       +1     
============================================
  Files            58       58              
  Lines          1475     1481       +6     
  Branches        114      116       +2     
============================================
+ Hits           1357     1364       +7     
+ Misses           79       78       -1     
  Partials         39       39              

Flag	Coverage Δ
ml-commons	92.09% <100.00%> (+0.09%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...rg/opensearch/ml/plugin/MachineLearningPlugin.java	100.00% <ø> (+1.81%)	⬆️
.../java/org/opensearch/ml/task/MLTaskDispatcher.java	100.00% <100.00%> (ø)
...main/java/org/opensearch/ml/utils/MLNodeUtils.java	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0573bb7...58e2c97. Read the comment docs.