In Standard Shields, significant text check should happen before partiness check

[StephenHeaps]

Description

On iOS, in Standard mode, cosmetically filtered content is hidden as soon as possible by hiding their element subtree, then after the content is hidden, we do another pass to check the subtree of the all these hidden elements to see if there is a 1st party or if they contain significant text](https://github.com/brave/brave-core/blob/master/ios/brave-ios/Sources/Brave/Frontend/UserContent/UserScripts/Scripts_Dynamic/Scripts/Sandboxed/SelectorsPollerScript.js#L446-L470). Hidden elements with 1st party URLs are unhidden, and so is content with significant text. iOS has a logic bug that differs from desktop here, where if a hidden element contains a 3rd party resource, we fail to check for significant text.

Desktop logic for this 'should unhide hidden element' check checks if the hidden subtree is first party or shows significant text is here: https://github.com/brave/brave-core/blob/ed5f49a24e74176420a40263075ad3580a10f7a8/components/cosmetic_filters/resources/data/content_cosmetic.ts#L559-L569

On iOS the logic for this same 'should unhide hidden element' check is here:
https://github.com/brave/brave-core/blob/ed5f49a24e74176420a40263075ad3580a10f7a8/ios/brave-ios/Sources/Brave/Frontend/UserContent/UserScripts/Scripts_Dynamic/Scripts/Sandboxed/SelectorsPollerScript.js#L560-L581

The bug on iOS occurs when the hidden element contains a 3rd party resource AND significant text. In this case, queryResults.foundThirdPartyResource is true so we enter that if block first and never check for significant text:
https://github.com/brave/brave-core/blob/ed5f49a24e74176420a40263075ad3580a10f7a8/ios/brave-ios/Sources/Brave/Frontend/UserContent/UserScripts/Scripts_Dynamic/Scripts/Sandboxed/SelectorsPollerScript.js#L567-L574

This is where iOS differs in the 'should unhide hidden element' check. See https://github.com/brave/internal/issues/1188 for STR.

[kjozwiak]

The above requires 1.69.170 or higher for 1.69.x verification 👍

[hffvld]

Verified on iPhone 14 and iPad Air using version(s):

Device/OS: 
- iPhone 14 / iOS 17.6.1
- iPad Air / iPadOS 16.7.2
Brave build: 1.69 (170)
BraveCore: 1.69.170 (128.0.6613.138)

---

Verification notes can be found via https://github.com/brave/internal/issues/1188#issuecomment-2344831684 and https://github.com/brave/internal/issues/1188#issuecomment-2344977815.