Make allow text and icon overlap true by default

Having the default value false, has led to confusion for our end users. The default value of false makes sense for symbols used in the style as labels and icons but for end-user added symbols, which are always important, we should not hide them by default. This is a breaking change and requires a semver major update.

```
symbolManager.setIconAllowOverlap(true);
symbolManager.setTextAllowOverlap(true);
```

Start by locating the implementation of symbolManager.setIconAllowOverlap(true) and symbolManager.setTextAllowOverlap(true), then inspect how their default values are defined. Change both defaults so end-user-added symbols allow overlap without explicit calls, and verify that style labels and icons retain their intended behavior. This is a breaking change requiring a semver major update.

Written by the indexing model from the issue text.