Authentication headers in Mojo and CLI 'validate' command

[SimoneDalka]

This PR adds authentication headers (if any) when fetching the OpenAPI definitions remotely.

Changes have been made on:

• validate command of openapi-generator-cli
• calculateInputSpecHash method in CodeGenMojo.java
• createCollapsedSpec method in CodeGenMojo.java

Resolves #19308, resolves #19108

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cc: @bbdouglas @sreeshas @jfiala @lukoyanov @cbornet @jeff9finger @karismann @Zomzog @lwlee2608 @martin-mfg

[wing328]

thanks for the PR

looks like this is the same as --auth option for generate

openapi-generator/modules/openapi-generator-cli/src/main/java/org/openapitools/codegen/cmd/Generate.java

Lines 76 to 81 in 45e1f73

	@Option(
	name = {"-a", "--auth"},
	title = "authorization",
	description = "adds authorization headers when fetching the OpenAPI definitions remotely. "
	+ "Pass in a URL-encoded string of name:header with a comma separating multiple values")
	private String auth;

[wing328]

cc @OpenAPITools/generator-core-team

[wing328]

thanks for the PR

let's give it a try