Update MongoDB docker image versions

[ebyhr]

The current versions have reached EOL: https://www.mongodb.com/legal/support-policy/lifecycles

MongoServer should use 6.x version. We will probably need to fix the command because there were some changes around TLS.

TestMongo4LatestConnectorSmokeTest should use 8.x and the class should be renamed to TestMongoLatestConnectorSmokeTest.

[joonseolee]

Can I take this ticket?

[Raj-G07]

@ebyhr Can i take this issue?

[vallimangai]

@joonseolee and @Raj-G07 are you both working on it?
if not i can take it up

[joonseolee]

@Raj-G07 @vallimangai

I will post a PR today :)