[Java] Fix skip negotiate null ref

[BrennanConroy]

Description

Using .shouldSkipNegotiate(true) with the SignalR Java client will null ref.

Customer Impact

Can't use the skip negotiate feature, useful for environments where you can't/wont enable sticky sessions, and/or always know WebSockets will be used.

Regression?

• Yes
• No

Regressed from 3.1

Risk

• High
• Medium
• Low

The issue is very obvious, the reason it wasn't found during the 5.0 release is because of an unfortunate piece of the testing that hid the issue. Fixed by writing a new test.

Verification

• Manual (required)
• Automated

Packaging changes reviewed?

• Yes
• No
• N/A

Addresses #29765

[ghost]

Hello human! Please make sure you've included the Shiproom Template in a comment or (preferably) the PR description. Also, make sure this PR is not marked as a draft and is ready-to-merge.

[halter73]

I think we could make it a bit more clear in the doc comments that the transport must explicitly be set to {@link TransportEnum.WEBSOCKETS} rather than it being something that happens automatically when you call .shouldSkipNegotiate(true).

aspnetcore/src/SignalR/clients/java/signalr/core/src/main/java/com/microsoft/signalr/HttpHubConnectionBuilder.java

Lines 70 to 77 in c925f99

	/**
	* Indicates to the {@link HubConnection} that it should skip the negotiate process.
	* Note: This option only works with the Websockets transport and the Azure SignalR Service require the negotiate step.
	*
	* @param skipNegotiate Boolean indicating if the {@link HubConnection} should skip the negotiate step.
	* @return This instance of the HttpHubConnectionBuilder.
	*/
	public HttpHubConnectionBuilder shouldSkipNegotiate(boolean skipNegotiate) {

[BrennanConroy]

Let this ruminate over the weekend, and I'm going to remove this check from the 5.0 change and add it to the main branch.
This would break folks who didn't set a transport and it would use WebSockets first by default but now would throw.