feat: introduce fixed font icons to tab navigation

[MartoYankov]

Add new property fixedIcons that defaults to true that fixes icon sizes to the spec size - 24x24 with max width 31 and max height 28 allowed. Set to false to use the actual size of the images.

[manoldonev]

@MartoYankov Android Bottom Navigation icon change scenario still does not look OK out-of-the-box but we'll investigate it after feature freeze (will log it).

[manoldonev]

@MartoYankov iOS Bottom Navigation font icons scenario -- third font icon gets clipped upon activation (will log it):

[manoldonev]

@MartoYankov iOS Tabs font icons scenario looks broken -- font icon color is wrong (will log it):

[manoldonev]

@MartoYankov iOS tabs icon change scenario still does not change the icon (will log it):

[MartoYankov]

@manoldonev

1. First one should be investigated.

2. Regarding the clipped icon - I believe this is expected. If you look closely the icon is clipped before the tab item is activated too. This is the case when the font is wrong and doesn't support icons. It's not an issue with the scaling, but with the font itself. If you do this in a Label the result will be the same.

3. Regarding the iOS Tabs icon colors, this is a decision/limitation I imposed. Since the color property can't apply on the titles (because of MDCTabBar limitation) I disabled it on the icons as well. Now for both the color property value of the TabStrip is the valid one. It's possible to do it for the icons since they are simply images, but looks weird.

[manoldonev]

test api19

[manoldonev]

@MartoYankov is the last (fourth) issue also a limitation of the MDCTabBar usage (about iOS tabs icon change example not working) or should I log it?