build: run lexer generation before parser generation

[ewanharris]

Description

We've been seeing intermittent failures with errors like below, after some investigation it became apparent that every instance of this error occurred when generateParser ran before generateLexer. So force the generateLexer task to run first using dependsOn

> Task :compileJava FAILED
/Users/ewan/dev/git/openfga/intellij-plugin/src/main/java/dev/openfga/intellijplugin/parsing/OpenFGAParserDefinition.java:50: error: cannot find symbol
        return new OpenFGAParser();
                   ^
  symbol:   class OpenFGAParser
  location: class OpenFGAParserDefinition

References

Review Checklist

• I have clicked on "allow edits by maintainers".
• I have added documentation for new/changed functionality in this PR or in a PR to openfga.dev [Provide a link to any relevant PRs in the references section above]
• The correct base branch is being used, if not main
• I have added tests to validate that the change in functionality is working as expected