Update attachment_html_smuggling_unescape.yml

[morriscode]

Depending on how the HTML is structured javascript identifiers never populates and this is present in strings only. Updating to accommodate.

[jkamdjou]

@morriscode failing Mimic FYI

[morriscode]

@morriscode failing Mimic FYI

that makes 0 sense, the existing logic is still there. Will review tho

[morriscode]

These regressions don't have any attachments, see notes and links to notion. I suspect they regressed for some other reason, however all of them are still firing rules in our platform, mostly BEC related rules. This change is safe to merge as the original matching criteria was never changed nor deleted, only expanded upon.

cc @jkamdjou

notion.so/EML-29740 - This email has 0 attachments. Regressing on it makes no sense. The rule would've never fired on this.
notion.so/EML-25460 - This email has 0 attachments. Regressing on it makes no sense. The rule would've never fired on this.
notion.so/EML-24589 - This email has 0 attachments. Regressing on it makes no sense. The rule would've never fired on this.
notion.so/EML-2396 - This email has 0 attachments. Regressing on it makes no sense. The rule would've never fired on this.
notion.so/EML-4236 - This email has 0 attachments. Regressing on it makes no sense. The rule would've never fired on this.
notion.so/EML-18055 - This email has 0 attachments. Regressing on it makes no sense. The rule would've never fired on this.
notion.so/EML-16923 - - This email has 0 attachments. Regressing on it makes no sense. The rule would've never fired on this.