Fixed cryptic error messages returned from Compile

[cmaglie]

Please check if the PR fulfills these requirements

• The PR has no duplicates (please search among the Pull Requests
  before creating one)
• The PR follows
  our contributing guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• UPGRADING.md has been updated with a migration guide (for breaking changes)

• What kind of change does this PR introduce?
  Fix the error messages from compile, they were not correctly encoded in the response.

• What is the current behavior?
  The message grpc: error while marshaling: proto: Marshal called with nil appeared instead of the real error message. See Compilation error: grpc: error while marshaling: proto: Marshal called with nil #1812 for details.

• What is the new behavior?
  The correct error message is outputted.

• Does this PR introduce a breaking change, and is titled accordingly?
  No

• Other information:
  Fix Compilation error: grpc: error while marshaling: proto: Marshal called with nil #1812

[codecov]

Codecov Report

Merging #1848 (dbfd94b) into master (f43c9ec) will decrease coverage by 0.06%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #1848      +/-   ##
==========================================
- Coverage   36.33%   36.26%   -0.07%     
==========================================
  Files         232      232              
  Lines       19496    19499       +3     
==========================================
- Hits         7083     7071      -12     
- Misses      11585    11597      +12     
- Partials      828      831       +3     

Flag	Coverage Δ
unit	36.26% <0.00%> (-0.07%)	⬇️

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

Impacted Files	Coverage Δ
commands/daemon/daemon.go	0.00% <0.00%> (ø)
arduino/monitor/monitor.go	41.05% <0.00%> (-6.32%)	⬇️

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[kittaakos]

I have verified it inside IDE2.

Steps I did:

• Download the latest nightly IDE2 build,

• Started IDE2, checked the version,

  Version: 2.0.0-rc9.2.nightly-20220824
  Date: 2022-08-24T03:48:57.272Z
  CLI Version: git-snapshot [04e70c53]
  
  Copyright © 2022 Arduino SA
  

• Without selecting a board, I compiled. It failed with the Marshal called with nil error. ✅

  grpc: error while marshaling: proto: Marshal called with nil
  
  Compilation error: grpc: error while marshaling: proto: Marshal called with nil
  

• I built the CLI manually from the cmaglie:fix_compile_err_marshaling branch.

  % git rev-parse --short HEAD
  dbfd94b8
  

• I dropped the CLI into the latest nightly IDE2 and ran a verify without setting the board. I could see the expected Missing FQBN (Fully Qualified Board Name) message. ✅

  Missing FQBN (Fully Qualified Board Name)
  
  Compilation error: Missing FQBN (Fully Qualified Board Name)
  

  

Thank you!

[kittaakos]

After merging this PR, please update the test_1 branch from the master. Thank you!

[per1234]

I verified this fixes #1812

Thanks Cristian!