fix: ENG-1451 Fixes for Dependabot (#287)

<!-- markdownlint-disable-next-line first-line-heading -->
## Description

- Docker now targets tests.
- Pip and Terraform updates are disabled and documented.
- TypeScript >=7.0.0 updates are ignored.
- Existing schedules and commit prefixes are preserved.

---------

Signed-off-by: Nick Miles <7bzbaedz8d@snkmail.com>

Author: terado

.github/dependabot.yaml

@@ -2,7 +2,7 @@ version: 2
 
 updates:
   - package-ecosystem: 'docker'
-    directory: '/'
+    directory: '/scripts/docker/tests'
     schedule:
       interval: 'daily'
     cooldown:
@@ -21,27 +21,10 @@ updates:
       # Prefix all commit messages with "chore: "
       prefix: 'chore'
 
-  - package-ecosystem: 'npm'
-    directory: '/'
-    schedule:
-      interval: 'daily'
-    cooldown:
-      default-days: 7
-    commit-message:
-      # Prefix all commit messages with "chore: "
-      prefix: 'chore'
-
-  - package-ecosystem: 'pip'
-    directory: '/'
-    schedule:
-      interval: 'daily'
-    cooldown:
-      default-days: 7
-    commit-message:
-      # Prefix all commit messages with "chore: "
-      prefix: 'chore'
+# No Python dependency manifest is present. Enable this ecosystem when one is added.
+# No Terraform dependency manifest is present. Enable this ecosystem when one is added.
 
-  - package-ecosystem: 'terraform'
+  - package-ecosystem: 'npm'
     directory: '/'
     schedule:
       interval: 'daily'