checker: extend byte deprecation warning to array init types

[ttytm]

Includes a small updated of the related code block as incremental refactor to improve readability and do less variable declarations and as casts.

🤖 Generated by Copilot at 0d1a731

Refactor vlib/v/checker/containers.v to use match and handle byte deprecation. Simplify vlib/x/json2/encoder.v by removing redundant case for []byte.

🤖 Generated by Copilot at 0d1a731

• Refactor the element symbol check for array types to use a match statement and handle ast.Alias (link)
• Remove the redundant case for []byte in the JSON encoder match statement (link)