Fixed integration test TestLibInstallMultipleSameLibrary

[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?

Fixed an integration test:

<<< Run completed (err = <nil>)
    json.go:90: 
        	Error Trace:	/home/runner/work/arduino-cli/arduino-cli/internal/integrationtest/lib/json.go:90
        	            				/home/runner/work/arduino-cli/arduino-cli/internal/integrationtest/lib/json.go:144
        	            				/home/runner/work/arduino-cli/arduino-cli/internal/integrationtest/lib/lib_test.go:100
        	Error:      	json data length does not match: expected=1, actual=3
        	Test:       	TestLibInstallMultipleSameLibrary
        	Messages:   	A duplicate library install has been detected

https://github.com/arduino/arduino-cli/actions/runs/3410728596/jobs/5674051391#step:6:955

What is the current behavior?

The test fails because a new release of the Arduino SigFox for MKRFox1200 library now has new dependencies.

What is the new behavior?

The test has been refined to actually check for duplicates installations of Arduino SigFox for MKRFox1200 instead of merely counting all the installed libraries.

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

No breaking changes