test: Fix sanitizer suppresions in streams_tests #24190

Two changes (that also make sense on their own) to remove the file-wide sanitizer suppression:

• FindByte no longer takes a char, but an uint8_t, after commit 196b4599201dbce3e0317e9b98753fa6a244b82d.
• The key vector of unsigned chars can be removed and inlined as initializer-list. This avoids a bunch of verbose code like clear() and push_back of chars.

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• #23962 (Use int32_t type for transaction size/weight consistently by hebasto)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

utACK faa630aa15bbda0f3b0cf3b6f31cf8fdaeb66975, I have reviewed the changes and agree it makes sense to merge