.Net: Processes - Sample Pattern Adjustments

[crickman]

Motivation and Context

Noticed some tiny stuff I wanted to make available for review, separate from the Agent sample.

Description

• LocalKernelProcessContext is IDisposable - Update to incorporate using statement to ensure disposal (best practice)
• Console.Write not resulting any output (`TextWriter.Write(char value) is an empty virtual method that requires override...or in this case interception - https://github.com/microsoft/referencesource/blob/master/mscorlib/system/io/textwriter.cs#L193.)
• Simplify ScriptedUserInputStep abstraction. State is never null and can be treated as such with a minor tweak. (Null check in the sample could be misleading - it gave me momentary pause)
• Removed redundant CreateKernelWithChatCompletion method where present (already in base class)
• Simplified Step01_Processes.ChatBotState initialization. The conditional inner initialization might be slightly misleading (It gave me momentary pause).

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄