Bump fl_chart version up to 0.70.0

[imaNNeo]

• FEATURE (by @Peetee06) Implemented a 5 years-old feature request about scroll and zoom support in our axis-based charts. Special thanks to @Peetee06 who made it happen, How to make scrollable x axis in flchart so that it looks nice not so compact in nature? #71
• IMPROVEMENT (by @Peetee06) Added functionality to control the transformation of axis-based charts using FlTransformationConfig class. You can now enable scaling and panning for LineChart, BarChart and ScatterChart using this class
• IMPROVEMENT (by @Peetee06) Added some new unit tests in bar_chart_data_extensions_test.dart, gradient_extension_test.dart and fixed a typo in bar_chart_data.dart
• BREAKING (by @Peetee06) Fixed the equatable functionality in our BarChart. We hope it will not affect anything in our chart, but because the behaviour is changed, we marked it as a breaking change. (read more here)
• BREAKING (by @Peetee06) BarChart is not const anymore due to adding an assert to check if transformations are allowed depending on the BarChartData.alignment property (read more here)
• IMPROVEMENT (by @Peetee06) Upgrade to the new Flutter version (3.27.0), Tests are failing on Flutter v3.27.0 #1804
• IMPROVEMENT (by @AliAkberAakash) Minor typo fix in our line chart documentation, fix typo in line_chart.md #1795
• IMPROVEMENT (by @imaNNeo) Fixed the code coverage API rate-limit issue
• Improvement (by @imaNNeo) Published the example app in Google Play and App Store. Other stores (such as snap store and Microsoft Store) will come next. You can download the Android version here in Google Play and the iOS version here in App Store

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.17%. Comparing base (fd52df2) to head (7d2cf3c).
Report is 1 commits behind head on main.

Additional details and impacted files

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  Coverage   93.17%   93.17%           
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  Files          45       45           
  Lines        3236     3236           
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  Hits         3015     3015           
  Misses        221      221           

Flag	Coverage Δ
flutter	93.17% <ø> (ø)

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