ci: Only set up Geo database for the 'rspec-ee' jobs

What does this MR do and why?

In #389439 (comment 1255333604), I noticed that the Geo database was set up even in rspec jobs, which are supposed to only run FOSS tests anyway.

To fix that, and reduce the likelihood of single-db jobs to fail due to that, this MR only set up Geo database in jobs that match rspec-ee or geo. I'm also changing the multi-db detection logic a bit from checking the presence of ee/ or DECOMPOSED_DB == "true" to checking the actual number of databases.

Test matrix

Job	Ok?
rspec predictive
rspec-ee predictive
rspec pg12	https://gitlab.com/gitlab-org/gitlab/-/jobs/3674011524
rspec pg13	https://gitlab.com/gitlab-org/gitlab/-/jobs/3674012114
rspec pg11	https://gitlab.com/gitlab-org/gitlab/-/jobs/3674011967
rspec pg12 single-db	https://gitlab.com/gitlab-org/gitlab/-/jobs/3674011604
rspec pg12 as-if-foss single-db	https://gitlab.com/gitlab-org/gitlab/-/jobs/3674011744
rspec-ee pg12	https://gitlab.com/gitlab-org/gitlab/-/jobs/3674011875
rspec-ee pg13	https://gitlab.com/gitlab-org/gitlab/-/jobs/3674012459
rspec-ee pg11	https://gitlab.com/gitlab-org/gitlab/-/jobs/3674012278
rspec-ee pg12 single-db	https://gitlab.com/gitlab-org/gitlab/-/jobs/3674011918
db:*	https://gitlab.com/gitlab-org/gitlab/-/jobs/3674011459

MR acceptance checklist

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