refactor(GuildMember): make _roles property non-enumerable

[Idris1401]

Please describe the changes this PR makes and why it should be merged:

I think it would be better to have GuildMember#roles to be defined as a "normal" property (dunno what's the right term) instead of a getter and make GuildMember#_roles a getter.
People are often console.loging data to get available properties and ._roles does appear in the log and .roles doesn't which makes people using a private property.
I was also told that this change could cause performance issue but I still wanted to make this PR to know everyone's thought about it.

I made another PR because I fucked up the branch in the old one.

Status and versioning classification:

• Code changes have been tested against the Discord API, or there are no code changes
• I know how to update typings and have done so, or typings don't need updating
• This PR changes the library's interface (methods or parameters added)

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[jaw0r3k]

It's still wrong

1. On patch it's updating the variable, and you can't set the getter
2. There is some reason why roles is a getter, as it relies on the _roles

[SpaceEEC]

I'd prefer _roles to be made non-enumerable over this change here, which would require further considerations (e.g. updates for all members when a role is deleted)

[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟠 Performance	84
🟢 Accessibility	100
🟢 Best practices	100
🟢 SEO	100
🟠 PWA	70

Lighthouse ran on https://discord-js-git-fork-idris1401-refactor-guildme-1aaea0-discordjs.vercel.app/

[Jiralite]

People are often console.loging data to get available properties and ._roles does appear in the log and .roles doesn't which makes people using a private property.

Frankly, that's their fault. Additionally, the property is prefixed with _ which is the convention for something that is private. I do not see this as a valid reason for this change. It instead seems like a reason to cater towards individuals that do not know what they are doing or know what they are doing is wrong.

Since #9529 landed, I am pretty sure this reverts the performance improvements.

[Idris1401]

I'd prefer _roles to be made non-enumerable over this change here, which would require further considerations (e.g. updates for all members when a role is deleted)

what does "non-enumerable" mean?

[SpaceEEC]

The descriptor parameter of Object.defineProperty has an enumerable property, setting that to false is what I meant.
I think we are doing this with the client field in the Base class.

[Idris1401]

The descriptor parameter of Object.defineProperty has an enumerable property, setting that to false is what I meant. I think we are doing this with the client field in the Base class.

based on MDN, enumerable is default set to false so I didn't add it