[AppBarLayout] Inconsistent default scrollFlags between XML and code

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**Description:**
`AppBarLayout.LayoutParams` defaults `scrollFlags` to `SCROLL_FLAG_SCROLL` (1) at field declaration, but XML inflation defaults to `0` (no scroll) when attribute is absent.

**Expected behavior:**
Both should default to `0` for consistency.

**Source code:**
```java
// Field declaration - defaults to 1
int scrollFlags = SCROLL_FLAG_SCROLL;
```

```java
// XML inflation - defaults to 0 when attribute missing
scrollFlags = a.getInt(R.styleable.AppBarLayout_Layout_layout_scrollFlags, 0);
```

**Workaround:**
Explicitly set `params.scrollFlags = 0` when creating programmatically.

Locate AppBarLayout.LayoutParams and compare the field declaration with the XML inflation path that reads layout_scrollFlags. Change the programmatic default to match the documented XML default of 0, then verify that both programmatic and XML-created parameters have no scroll flags when none are specified.

Written by the indexing model from the issue text.