Update crash reporting readme

[issackjohn]

This pull request includes updates to the CrashReporting/AddStackToCrashReports.md document to provide clearer guidance on handling call stacks in crash reports.

Privacy Enhancements:

• Included feedback on mitigating privacy issues by either omitting JavaScript call stacks with extension scripts or prompting users with explanations about sensitive information.

Clarifications on Call Stack Handling:

• Provided additional context on why an explicit opt-in is required for sites to capture call stacks, aligning with privacy concerns.

Document Formatting:

• Added spacing to improve readability and structure of the document. [1] [2]

[issackjohn]

@sethbrenith could I get your review of this? If it looks good to you i'll open a PR on the official repo for review.

[issackjohn]

Context

https://groups.google.com/a/chromium.org/g/blink-dev/c/5W-TJDTz7pE/m/pIftgg2wCgAJ --> Asked to clarify so I'm clarifying.

w3ctag/design-reviews#981 --> I'm incorporating their feedback in the explainer