fix(math): double method call (#15768)

## Description
The `init` method of the `Rand` struct was called twice: in the constructor and in the `init` function.
Closes: #XXXX



---

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* [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
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* [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
* [ ] confirmed `!` in the type prefix if API or client breaking change
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math/CHANGELOG.md

@@ -40,6 +40,10 @@ Ref: https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.j
 
 * [#15714](https://github.com/cosmos/cosmos-sdk/pull/15714) `FormatInt` returns an error on empty string
 
+### Improvements
+
+* [#15768](https://github.com/cosmos/cosmos-sdk/pull/15768) Removed the second call to the `init` method for the global variable `grand`.
+
 ## [math/v1.0.0](https://github.com/cosmos/cosmos-sdk/releases/tag/math/v1.0.0) - 2023-03-23
 
 ### Bug Fixes

math/unsafe/rand.go

@@ -26,7 +26,6 @@ var grand *Rand
 
 func init() {
 	grand = NewRand()
-	grand.init()
 }
 
 func NewRand() *Rand {