Fix country note list ordering

[qwoprocks]

Description

As per title. Changed from comparing note contents, to actual added order.

Fixes #

Testing

Added and deleted some country notes.

Remarks

NIL.

[codecov]

Codecov Report

Merging #274 into master will increase coverage by 0.16%.
The diff coverage is 83.33%.

@@             Coverage Diff              @@
##             master     #274      +/-   ##
============================================
+ Coverage     86.62%   86.78%   +0.16%     
- Complexity      944      945       +1     
============================================
  Files           113      113              
  Lines          2459     2459              
  Branches        275      274       -1     
============================================
+ Hits           2130     2134       +4     
+ Misses          252      248       -4     
  Partials         77       77              

Impacted Files	Coverage Δ	Complexity Δ
...ain/java/seedu/address/model/note/CountryNote.java	100.00% <ø> (+17.39%)	12.00 <0.00> (ø)
...main/java/seedu/address/model/country/Country.java	90.90% <50.00%> (+0.43%)	12.00 <2.00> (+1.00)
...rc/main/java/seedu/address/model/ModelManager.java	94.69% <100.00%> (+0.14%)	43.00 <1.00> (ø)

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[raysonkoh]

Manually tested country note add and country note delete, seems to be working as expected. So just to check, a country note will first be sorted by country code, then insertion order right?

[qwoprocks]

Manually tested country note add and country note delete, seems to be working as expected. So just to check, a country note will first be sorted by country code, then insertion order right?

@raysonkoh yup correct

[raysonkoh]

LGTM