refactor: remove redundant sandbox flag (#85)

The `sandbox` input for the `google-github-actions/run-gemini-cli`
action defaults to `false`. This commit removes the explicit `sandbox:
false` setting from the workflows, as it is redundant.

Author: jerop

.github/workflows/gemini-cli.yml

@@ -312,8 +312,7 @@ jobs:
               "telemetry": {
                 "enabled": true,
                 "target": "gcp"
-              },
-              "sandbox": false
+              }
             }
           prompt: |-
             ## Role & Goal

.github/workflows/gemini-issue-automated-triage.yml

@@ -83,8 +83,7 @@ jobs:
               "telemetry": {
                 "enabled": true,
                 "target": "gcp"
-              },
-              "sandbox": false
+              }
             }
           prompt: |-
             ## Role

.github/workflows/gemini-issue-scheduled-triage.yml

@@ -93,8 +93,7 @@ jobs:
               "telemetry": {
                 "enabled": true,
                 "target": "gcp"
-              },
-              "sandbox": false
+              }
             }
           prompt: |-
             ## Role

.github/workflows/gemini-pr-review.yml

@@ -196,8 +196,7 @@ jobs:
               "telemetry": {
                 "enabled": true,
                 "target": "gcp"
-              },
-              "sandbox": false
+              }
             }
           prompt: |-
             ## Role

workflows/gemini-cli/gemini-cli.yml

@@ -312,8 +312,7 @@ jobs:
               "telemetry": {
                 "enabled": true,
                 "target": "gcp"
-              },
-              "sandbox": false
+              }
             }
           prompt: |-
             ## Role & Goal

workflows/issue-triage/gemini-issue-automated-triage.yml

@@ -83,8 +83,7 @@ jobs:
               "telemetry": {
                 "enabled": true,
                 "target": "gcp"
-              },
-              "sandbox": false
+              }
             }
           prompt: |-
             ## Role

workflows/issue-triage/gemini-issue-scheduled-triage.yml

@@ -93,8 +93,7 @@ jobs:
               "telemetry": {
                 "enabled": true,
                 "target": "gcp"
-              },
-              "sandbox": false
+              }
             }
           prompt: |-
             ## Role

workflows/pr-review/gemini-pr-review.yml

@@ -196,8 +196,7 @@ jobs:
               "telemetry": {
                 "enabled": true,
                 "target": "gcp"
-              },
-              "sandbox": false
+              }
             }
           prompt: |-
             ## Role