fix: upgrade https-proxy-agent from 7.0.2 to 7.0.6

Snyk has created this PR to upgrade https-proxy-agent from 7.0.2 to 7.0.6.

See this package in npm:
https-proxy-agent

See this project in Snyk:
https://app.snyk.io/org/mountebank-testing/project/0299f531-dd33-4a40-b36d-f6244d3c2a9c?utm_source=github&utm_medium=referral&page=upgrade-pr

Author: snyk-bot

package-lock.json

@@ -62,7 +62,7 @@
     "express": "5.1.0",
     "fs-extra": "11.2.0",
     "http-proxy-agent": "7.0.0",
-    "https-proxy-agent": "7.0.2",
+    "https-proxy-agent": "7.0.6",
     "jsonpath-plus": "10.3.0",
     "mailparser": "3.7.4",
     "nodemailer": "6.10.1",