Enable gocritic offBy1 and fix import warning slicing (codex) (#3713)

## Changes
- enable the gocritic offBy1 check in golangci-lint so we catch missing
Index() bounds handling
- guard the Terraform import warning truncation against missing
"Warning:" blocks to avoid slice panics

------
https://chatgpt.com/s/cd_68df8308cdf081918babe8e111fb5dce

Author: denik

.golangci.yaml

@@ -31,6 +31,7 @@ linters:
       disable-all: true
       enabled-checks:
         - ruleguard
+        - offBy1
       settings:
         ruleguard:
           failOn: all

bundle/deploy/terraform/import.go

@@ -71,8 +71,10 @@ func (m *importResource) Apply(ctx context.Context, b *bundle.Bundle) diag.Diagn
 
 	if changed && !m.opts.AutoApprove {
 		output := buf.String()
-		// Remove output starting from Warning until end of output
-		output = output[:strings.Index(output, "Warning:")]
+		// Remove output starting from Warning until end of output, if present.
+		if idx := strings.Index(output, "Warning:"); idx != -1 {
+			output = output[:idx]
+		}
 		cmdio.LogString(ctx, output)
 
 		if !cmdio.IsPromptSupported(ctx) {