Revert "Fix bigtable_custom_endpoint ignoring config and dropping gRPC endpoints"

[roaks3]

Reverts #16958

This caused a number of our nightly tests to fail, so it would seem something wasn't working and we need more robust testing

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes for commit ee1d4e3:

Diff report

Your PR generated the following diffs in downstream repositories:

Repository	Diff Link	Changes
google provider	View Diff	2 files changed, 29 insertions(+), 128 deletions(-)
google-beta provider	View Diff	2 files changed, 29 insertions(+), 128 deletions(-)

Test report

Analytics

Total Tests	Passed	Skipped	Affected
66	0	66	0

Affected Service Packages

• bigtable

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@roaks3, @SirGitsalot VCR tests complete for ee1d4e3!

[SirGitsalot]

Example failure log:

------- Stdout: -------
=== RUN   TestAccBigtableAppProfile_bigtableAppProfileAnyclusterExample
=== PAUSE TestAccBigtableAppProfile_bigtableAppProfileAnyclusterExample
=== CONT  TestAccBigtableAppProfile_bigtableAppProfileAnyclusterExample
    resource_bigtable_app_profile_generated_test.go:68: Step 1/3 error: Error running apply: exit status 1
        Error: Error creating instance. rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing: dial tcp: address bigtableadmin.googleapis.com: missing port in address"
          with google_bigtable_instance.instance,
          on terraform_plugin_test.tf line 12, in resource "google_bigtable_instance" "instance":
          12: resource "google_bigtable_instance" "instance" {
--- FAIL: TestAccBigtableAppProfile_bigtableAppProfileAnyclusterExample (5.18s)
FAIL

[SirGitsalot]

@mhandugan