fix(cloudrun): use errors.Join in Close() so both errors propagate (#4986)

Previous Close() returned only the first error if both client closes
failed — the second was silently dropped:

    if sErr != nil {
        return sErr
    }
    return rErr

errors.Join (Go 1.20+) preserves both, simpler, no behavior change
when only one fails. Low-impact for a short-lived CLI but cheap
to do right.

Addresses two duplicate review comments on PR 833.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: ToreMerkely

internal/cloudrun/cloudrun.go

@@ -6,6 +6,7 @@ package cloudrun
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"strings"
 	"time"
@@ -64,19 +65,14 @@ func New(ctx context.Context) (*Client, error) {
 }
 
 // Close releases the underlying gRPC connections. Safe to call on a Client
-// constructed with a fake apiClient (returns nil). Returns the first error
-// from closing either client; the second is always attempted.
+// constructed with a fake apiClient (returns nil). Both clients are always
+// closed; errors from each are joined so neither is silently dropped.
 func (c *Client) Close() error {
 	g, ok := c.api.(*gcpAPI)
 	if !ok {
 		return nil
 	}
-	sErr := g.services.Close()
-	rErr := g.revisions.Close()
-	if sErr != nil {
-		return sErr
-	}
-	return rErr
+	return errors.Join(g.services.Close(), g.revisions.Close())
 }
 
 // ListServices returns every Cloud Run service in the given project+region,