fix: dont allow paths in grpc protocol

[rakesh-garimella]

Description

Changes proposed in this pull request (what was done and why):

• grpc protocol does not support path
• When we set the path along with port its not validated. eg. https://foo.bar:4317/my/path was accepted and caused the otel collector to crashloop.

Changes refer to particular issues, PRs or documents:

• Missing validation when grpc protocol is set in endpoint is defined with path #3035

Traceability

• The PR is linked to a GitHub issue.
• The follow-up issues (if any) are linked in the Related Issues section.
• If the change is user-facing, the documentation has been adjusted.
• If a CRD is changed, the corresponding Busola ConfigMap has been adjusted.
• The feature is unit-tested.
• The feature is e2e-tested.