Fix mangled endpoint

[darnaut]

Description

Some commands were failing with DNS resolution errors:

spacectl api --schema     
2026/07/27 16:11:33 error executing request: Post "https://spacelift.foobar.o/graphql": dial tcp: lookup spacelift.foobar.o: no such host

The problem is that strings.TrimRight trims any trailing characters found in the /graphql cutset, which mangled hosts that end with characters in the /graphql set (such as .org, .ph, etc).

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Other (please describe):

Changes Made

• Replaced strings.TrimRight with strings.TrimSuffix as recommended by Go's documentation.

Testing

• I have tested these changes locally
• I have added/updated tests as needed
• All existing tests pass

Checklist

• My code follows the project's style guidelines
• I have performed a self-review of my code
• I have commented my code where necessary
• My changes generate no new warnings