…id using an uninitialized variable in path calculation.

27ee53c wallet: Add error handling. Check return value of ParseUInt32(...) in ParseHDKeypath(...). (practicalswift)
7223263 wallet: Add tests for ParseHDKeypath(...) (practicalswift)

Pull request description:

  Add error handling. Check return value of `ParseUInt32(...)` in `ParseHDKeypath(...)`.

  `ParseUInt32(...)` returns `false` if the entire string could not be parsed or when an overflow or underflow occurred. In such case the uninitialized variable `number` would be used in the calculation of `path` (prior to this commit).

  An example key path triggering this is `m/0/4294967296`:

  ```
    ParseHDKeypath("m/0/4294967296", keypath);
  ```

  `4294967296` is `1` + `0xFFFFFFFF` (`uint32_t` max: `4294967295`).

  Introduced in a4b06fb which was merged into `master` 14 hours ago as part of #13557 ("BIP 174 PSBT Serializations and RPCs").

Tree-SHA512: e5ff423f67c18d82c1231bde6343587a453e793c32004d93dc9b61be6d9372b57a6b2c9978d9eb1000d6cc82fd180f2486013f928dca737fb92daad22c16e467

… functions returning bool

9cc0230 Add NODISCARD to all {Decode,Parse}[...](...) functions returning bool. Sort includes. (practicalswift)
579497e tests: Explicitly ignore the return value of DecodeBase58(...) (practicalswift)
145fe95 tests: Check return value of ParseParameters(...) (practicalswift)
7c5bc2a miner: Default to DEFAULT_BLOCK_MIN_TX_FEE if unable to parse -blockmintxfee (practicalswift)

Pull request description:

  Changes in this PR:
  * ~~Add linter to make sure the return value of `Parse[...](...)` is checked~~
  * Add `__attribute__((warn_unused_result))` to all `{Decode,Parse}[...](...)` functions returning `bool`
  * Fix violations

  Context:
  * #13712: `wallet: Fix non-determinism in ParseHDKeypath(...). Avoid using an uninitialized variable in path calculation.` would have been prevented by this

Tree-SHA512: 41a97899f2d5a26584235fa02b1ebfb4faacd81ea97e927022955a658fa7e15d07a1443b4b7635151a43259a1adf8f2f4de3c1c75d7b5f09f0d5496463a1dae6