Enable the LS code suggestions cache by default

This MR in the LS enabled the code suggestions cache when no configuration is applied: gitlab-org/editor-extensions/gitlab-lsp!167 (merged)

However, the cache was not default-enabled in the Workflow extension, because the configuration sent to the Language Server is overridden with { enabled: false }, whenever local settings.json cache config is not set.

This was likely not noticed among all of the initial testers of the cache, because we asked everyone to add the cache setting to their user settings.

The end result is that for most general users, the suggestions cache is not currently enabled.

Proposal

Remove the enabled: false default in the Workflow extension, thus enabling the code suggestions cache by default.