Fix: Return result object on failure in Invoke-D365ModuleBuild

[es-alficody]

Follow-up to #923.

• Success prints only the result object, no summary block
• Failure prints the compiler error lines, then the same result object with Success=False last
• Only 'Compile Error' diagnostic lines are printed, warning lines are excluded again
• Removes the now-unused summary variables (keeps PSScriptAnalyzer clean)