Sync availability in settings (non 0.58.x)

[darkdh]

follow up of #2642 (comment)

[GeetaSarvadnya]

@darkdh brave/brave-core#1145 (comment)
Brave sync section is still shown when we launch brave with --disable-brave-sync

Issue is reproducible on

Brave	0.59.12 Chromium: 72.0.3626.17 (Official Build) beta (64-bit)
Revision	08d2140079f8db14c9eb885a803d231b1a30e817-refs/branch-heads/3626@{#315}
OS	Windows

[darkdh]

0.59.12 doesn't contain the fix, please retest with 0.59.13 when it is available

[GeetaSarvadnya]

Verification passed on

Brave	0.59.13 Chromium: 72.0.3626.28 (Official Build) beta (64-bit)
Revision	997b1040b63bac324e815797ba52be0cd8f616ed-refs/branch-heads/3626@{#461}
OS	Windows

• Verified there is no sync section in chrome settings and Hamburger menu when we launch brave with --disable-brave-sync flag
  
• Verified there is sync section in both chrome://settings and Hamburger menu when we lauch brave without --disable-brave-sync flag
  
• Logged new issue (searching via settings causes "Uncaught Error: Assertion failed: An associated control was expected for SETTINGS-SUBPAGE Manage sync, but was not found." and spinner doesn't stop animating #2757)

Verification passed on

Brave 0.59.13 Chromium: 72.0.3626.28 (Official Build) beta (64-bit)
Revision 997b1040b63bac324e815797ba52be0cd8f616ed-refs/branch-heads/3626@{#461}
OS Linux

• Brave sync is not renamed to Sync in Hamburger menu hence logged new issue (Brave sync is not renamed to Sync on Linux platform #2758).

• Verified there is sync section in both chrome://settings and Hamburger menu when we lauch brave without --disable-brave-sync flag
  

• Verified there is no sync section in chrome settings and Hamburger menu when we launch brave with --disable-brave-sync flag
  

Verified passed with

Brave	0.59.14 Chromium: 72.0.3626.28 (Official Build) beta(64-bit)
Revision	997b1040b63bac324e815797ba52be0cd8f616ed-refs/branch-heads/3626@{#461}
OS	Mac OS X

• Verified test plan from Displaying sync in setting according to sync enable/disable status brave-core#1145
  When Brave is NOT launched with --disable-brave-sync, Sync is available and brave://sync page loads:
  
  

When Brave IS launched with --disable-brave-sync, Sync is not available and brave://sync page does not load: