chore: remove key comparison check to fix gitsshkey flake (#8002)

In tests we use weak randomness and the same key was generated which
caused a test flake here.

coderd/gitsshkey_test.go

@@ -92,7 +92,6 @@ func TestGitSSHKey(t *testing.T) {
 		require.NoError(t, err)
 		require.GreaterOrEqual(t, key2.UpdatedAt, key1.UpdatedAt)
 		require.NotEmpty(t, key2.PublicKey)
-		require.NotEqual(t, key2.PublicKey, key1.PublicKey)
 
 		require.Len(t, auditor.AuditLogs(), 2)
 		assert.Equal(t, database.AuditActionWrite, auditor.AuditLogs()[1].Action)