If ledger not enabled, honor settings for clearing history

[mrose17]

• Did you search for similar issues before submitting this one? yes

• Describe the issue you encountered: if the ledger isn't enabled, then the user's settings for clearing history should be honored

• Platform (Win7, 8, 10? macOS? Linux distro?): all

• Brave Version (revision SHA): n/a

• Steps to reproduce:

  1. do not enable the ledger
  2. visit various sites
  3. go to about:preferences#security and under "Private Data" enable "Browsing history" to be cleared and then quit the browser
  4. or go to about:preferences#security and click "Clear Browsing Data Now...", enable "Browsing history" to be cleared

• Actual result: ledger-synopsis files are not removed

• Expected result: ledger-files files are not removed

• Will the steps above reproduce in a fresh profile? If not what other info can be added? no, you need to visit some

• Is this an issue in the currently released version? yes

• Can this issue be consistently reproduced? yes

• Extra QA steps: none

• Screenshot if needed: none

• Any related issues: Auto-purging "Saved site settings" resets Payments "Include" toggles #6708 deals with moving ledger-specific settings for sites from site settings to the ledger-synopsis file

[bsclifton]

Pulling into 0.15.0 since this can speed up load times. PR submitted with #8496

[mrose17]

hooray!