fix(table): fix stack list silent crash on null resource_control

[FAZuH]

wrpt stack list silently fails and results in empty output if there exists a stack with null StackList::resource_control.

This PR:

• Changes the type from ResourceControl to Option<ResourceControl> so the command does not fail silently.
• Parses serde_json::Value::Null into an empty string to prevent the value showing as null.
• Adds an unit test to verify that a stack with "ResourceControl": null in the API response correctly deserializes to StackList with resource_control: None rather than crashing.

Note that Stack in src/commands/stacks/models/deploy.rs does not need any changes since the resource_control is already Option<ResourceControl>

󰣇 ~/Projects/wrpt   HEAD(5080bbc)   $ ❮ rg 'resource_control: '                                                                                                                                                             rs    22:10
src/commands/stacks/models/list.rs
23:    pub(crate) resource_control: ResourceControl,

src/commands/stacks/models/deploy.rs
60:    pub(crate) resource_control: Option<ResourceControl>,