Handle Redis DMS target endpoint correctly

[dpattmann]

Community Note

• Please vote on this pull request by adding a 👍 reaction to the original pull request comment to help the community and maintainers prioritize this request
• Please do not leave "+1" or other comments that do not add relevant new information or questions, they generate extra noise for pull request followers and do not help prioritize the request

Closes #26266

Output from acceptance testing:

$ make testacc TESTARGS='-run=TestAccDMSEndpoint_Redis_' PKG=dms
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./internal/service/dms/... -v -count 1 -parallel 20  -run=TestAccDMSEndpoint_Redis_ -timeout 180m
=== RUN   TestAccDMSEndpoint_Redis_basic
=== PAUSE TestAccDMSEndpoint_Redis_basic
=== RUN   TestAccDMSEndpoint_Redis_update
=== PAUSE TestAccDMSEndpoint_Redis_update
=== CONT  TestAccDMSEndpoint_Redis_basic
=== CONT  TestAccDMSEndpoint_Redis_update
--- PASS: TestAccDMSEndpoint_Redis_basic (103.42s)
--- PASS: TestAccDMSEndpoint_Redis_update (118.68s)
PASS
ok  	github.com/hashicorp/terraform-provider-aws/internal/service/dms	120.368s

[dpattmann]

There is already another PR #26411 handling issue #26266. Going to close this PR.

[peresypkinroman]

We did PRs almost simultaneously.
If you have smth to add or to reason fill free.

[github-actions]

I'm going to lock this pull request because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.
If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.