Add shmSize to management flag's init

[katiewasnothere]

Type of Change

• Bug fix

Motivation and Context

Ensure all fields are initialized in the management flags' init function. Without this change, if someone calls init() on this set of flags, they will get an error like

Can't read a value from a parsable argument definition.

This error indicates that a property declared with an `@Argument`,
`@Option`, `@Flag`, or `@OptionGroup` property wrapper was neither
initialized to a value nor decoded from command-line arguments.

To get a valid value, either call one of the static parsing methods
(`parse`, `parseAsRoot`, or `main`) or define an initializer that
initializes _every_ property of your parsable type.

Testing

• Tested locally

[github-actions]

Code Coverage

Tier	Line Coverage
Unit	33.52%
Integration	19.55%
Combined	52.51%

[hernandezadonai587]

Q