disable update checking on unofficial build

[RacoonDog]

Type of change

• Bug fix
• New feature

Description

Disable update checking on unofficial builds

"unofficial builds" meaning those where the build_number property is unset when compiling, making the MeteorClient#BUILD_NUMBER variable contain an empty string

disabling update checking also suppresses this stacktrace that appears in the logs when MeteorClient#BUILD_NUMBER cannot be parsed to an int

[22:09:19] [Render thread/INFO] (Meteor Client) Checking latest version of Meteor Client
[22:09:19] [Meteor-Executor-1/ERROR] (FabricLoader) Uncaught exception in thread "Meteor-Executor-1"
java.lang.NumberFormatException: For input string: ""
	at java.base/java.lang.NumberFormatException.forInputString(NumberFormatException.java:67) ~[?:?]
	at java.base/java.lang.Integer.parseInt(Integer.java:671) ~[?:?]
	at java.base/java.lang.Integer.parseInt(Integer.java:777) ~[?:?]
	at knot/net.minecraft.client.gui.screen.TitleScreen.mddc5b07$meteor-client$lambda$onRenderIdkDude$3$0(TitleScreen.java:557) ~[minecraft-merged-e95e5615d8-1.21.4-net.fabricmc.yarn.1_21_4.1.21.4+build.7-v2.jar:?]
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) ~[?:?]
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) ~[?:?]
	at java.base/java.lang.Thread.run(Thread.java:1583) [?:?]

How Has This Been Tested?

Videos or screenshots of the changes if testicable.

Checklist:

• My code follows the style guidelines of this project.
• I have added comments to my code in more complex areas.
• I have tested the code in both development and production environments.