GH4286: Update DotNetToolRunner to append command using quotes

[antonysmith-mandogroup]

As per discussion in #4286, this PR resolves an issue where the command passed to DotNetToolRunner is the path of an application to run and it contains whitespace.

Sample verbose output before this change:

begin /k:"test-project" /n:"Test Project" /d:sonar.login="[REDACTED]"
We're launching for CoreCLR with executable C:/tmp/Cake Test/tools/dotnet-sonarscanner.10.3.0/tools/netcoreapp3.1/any/SonarScanner.MSBuild.dll
Resolved tool to path C:/Program Files/dotnet/dotnet.exe
Executing: "C:/Program Files/dotnet/dotnet.exe" C:/tmp/Cake Test/tools/dotnet-sonarscanner.10.3.0/tools/netcoreapp3.1/any/SonarScanner.MSBuild.dll begin /k:"test-project" /n:"Test Project" /d:sonar.login="[REDACTED]"
Could not execute because the specified command or file was not found.
Possible reasons for this include:
  * You misspelled a built-in dotnet command.
  * You intended to execute a .NET program, but dotnet-C:/tmp/Cake does not exist.
  * You intended to run a global tool, but a dotnet-prefixed executable with this name could not be found on the PATH.
An error occurred when executing task 'Sonar-Qube-Start-Analysis'.

Output following the change - note the surrounding quotes around the application being run:

begin /k:"test-project" /n:"Test Project" /d:sonar.login="[REDACTED]"
We're launching for CoreCLR with executable C:/tmp/Cake Test/tools/dotnet-sonarscanner.10.3.0/tools/netcoreapp3.1/any/SonarScanner.MSBuild.dll
Resolved tool to path C:/Program Files/dotnet/dotnet.exe
Executing: "C:/Program Files/dotnet/dotnet.exe" "C:/tmp/Cake Test/tools/dotnet-sonarscanner.10.3.0/tools/netcoreapp3.1/any/SonarScanner.MSBuild.dll" begin /k:"test-project" /n:"Test Project" /d:sonar.login="[REDACTED]"
SonarScanner for MSBuild 10.3
Using the .NET Core version of the Scanner for MSBuild
Pre-processing started.

All unit tests (that I can run on my Windows machine) pass:

This includes a new test I have added to verify that the command is now quoted.

[antonysmith-mandogroup]

@microsoft-github-policy-service agree company="Mando Group"

[devlead]

LGTM

[devlead]

@antonysmith-mandogroup your changes have been merged, thanks for your contribution 👍