cobalt: Disable HSTS Preload List

[borongc]

Disable the HSTS (HTTP Strict Transport Security) preloaded list
to reduce binary size. This change saves approximately 1.3 MB of
read-only data. Cobalt is a closed app shell and does not require
the comprehensive list of third-party domains provided by Chromium.

# original
> du -s out/android-arm_qa/libchrobalt.so
70748	out/android-arm_qa/libchrobalt.so
> du -s out/android-arm_qa/apks/Cobalt.apk
89472	out/android-arm_qa/apks/Cobalt.apk
> du -s out/evergreen-arm-hardfp-rdk_qa/libcobalt.so
78992	out/evergreen-arm-hardfp-rdk_qa/libcobalt.so

# include_transport_security_state_preload_list = false
> du -s out/android-arm_qa/libchrobalt.so
69452	out/android-arm_qa/libchrobalt.so
> du -s out/android-arm_qa/apks/Cobalt.apk
88176	out/android-arm_qa/apks/Cobalt.apk
> du -s out/evergreen-arm-hardfp-rdk_qa/libcobalt.so
78992	out/evergreen-arm-hardfp-rdk_qa/libcobalt.so

Issue: 520903111

[github-actions]

🤖 Gemini Suggested Commit Message

---

build: Disable HSTS preload list

Disable the HSTS preloaded list to reduce binary size. This change
saves approximately 1.3 MB of read-only data. Cobalt is a closed
app shell and does not require the comprehensive list of third-party
domains provided by Chromium.

Issue: 520903111

---

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[gemini-code-assist]

Code Review

This pull request disables the HSTS preload list in cobalt/build/configs/common.gn to reduce binary size. The reviewer pointed out that disabling a feature for binary size optimization must follow the surgical feature removal pipeline and guidelines documented in SKILL.md, which this PR currently lacks.