Added {sketch_path} to build properties

[cmaglie]

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• Tests for the changes have been added (for bug fixes / features)
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What kind of change does this PR introduce?

Adds the missing sketch_path variable to the build properties.

What is the current behavior?

{sketch_path} is missing from the build properties:

$ arduino-cli compile -b arduino:avr:uno --show-properties | grep sketch_path
$

What is the new behavior?

{sketch_path} is present in the build properties:

$ arduino-cli compile -b arduino:avr:uno --show-properties | grep sketch_path
sketch_path=/home/cmaglie/Arduino/Blink
$

Does this PR introduce a breaking change, and is titled accordingly?

No

Other information

Fix #2340

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (a1fad63) 62.81% compared to head (c1494f1) 62.82%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2372   +/-   ##
=======================================
  Coverage   62.81%   62.82%           
=======================================
  Files         204      204           
  Lines       19308    19311    +3     
=======================================
+ Hits        12129    12132    +3     
  Misses       6119     6119           
  Partials     1060     1060           

Flag	Coverage Δ
unit	62.82% <100.00%> (+<0.01%)	⬆️

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Files	Coverage Δ
arduino/builder/builder.go	65.78% <100.00%> (+0.30%)	⬆️

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