fix(java): fix config_overrides for tests (#3968)

## Description
Problem
In the default configuration `opts.test` is a boolean and the code tries
to access `opts.test.config_overrides` which results in an error.

Solution
Use control flow to return nil in the case of `opts.test` being boolean.

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  why we should accept this pull request. -->

## Related Issue(s)
  - Fixes #3965.

## Checklist

- [ x] I've read the
[CONTRIBUTING](https://github.com/LazyVim/LazyVim/blob/main/CONTRIBUTING.md)
guidelines.

lua/lazyvim/plugins/extras/lang/java.lua

@@ -227,13 +227,17 @@ return {
                   ["<leader>t"] = { name = "+test" },
                   ["<leader>tt"] = {
                     function()
-                      require("jdtls.dap").test_class({ config_overrides = opts.test.config_overrides })
+                      require("jdtls.dap").test_class({
+                        config_overrides = type(opts.test) ~= "boolean" and opts.test.config_overrides or nil,
+                      })
                     end,
                     "Run All Test",
                   },
                   ["<leader>tr"] = {
                     function()
-                      require("jdtls.dap").test_nearest_method({ config_overrides = opts.test.config_overrides })
+                      require("jdtls.dap").test_nearest_method({
+                        config_overrides = type(opts.test) ~= "boolean" and opts.test.config_overrides or nil,
+                      })
                     end,
                     "Run Nearest Test",
                   },