CA fingerprint comparison of SHA-256 strings should support both colon-separated hex string and lowercase string

[JoshMock]

🐛 Bug Report

As noted in observablehq/framework#1490, the caFingerprint option fails when comparing a SHA-256 string that is provided as all lowercase, no colons (e.g. a1b2c3d4 rather than A1:B2:C3:D4). The lowercase format is what Elasticsearch prints to the console on startup, which fails the string comparison and is a confusing experience. All fingerprints should be normalized to the same format before comparison.

[JoshMock]

Just released this in v8.7.1.